Apparatus for transmitting broadcast signals, apparatus for receiving broadcast signals, method for transmitting broadcast signals and method for receiving broadcast signals

ABSTRACT

A method and an apparatus for receiving broadcast signals thereof are disclosed. The apparatus for receiving broadcast signals, the apparatus comprises a receiver to receive the broadcast signals, a demodulator to perform demodulation on the received broadcast signals by an OFDM (Orthogonal Frequency Division Multiplex) scheme, a frequency de-interleaver to frequency de-interleave the demodulated broadcast signals by using a different interleaving sequence, wherein the different interleaving sequence is used for data corresponding to an OFDM symbol pair or data corresponding to an OFDM symbol according to an FFT size of the demodulation, a frame parser to parse at least one signal frame from the frequency de-interleaved broadcast signals and a decoder to decode service data in the parsed at least one signal frame.

This application claims the benefit of U.S. Provisional Application Nos.62/112,650, 62/120,338, 62/133,482 and 62/152,038, filed on Feb. 6,2015, Feb. 24, 2015, Mar. 16, 2015 and Apr. 24, 2015 which are herebyincorporated by reference as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for transmitting broadcastsignals, an apparatus for receiving broadcast signals and methods fortransmitting and receiving broadcast signals.

2. Discussion of the Related Art

As analog broadcast signal transmission comes to an end, varioustechnologies for transmitting/receiving digital broadcast signals arebeing developed. A digital broadcast signal may include a larger amountof video/audio data than an analog broadcast signal and further includevarious types of additional data in addition to the video/audio data.

That is, a digital broadcast system can provide HD (high definition)images, multi-channel audio and various additional services. However,data transmission efficiency for transmission of large amounts of data,robustness of transmission/reception networks and network flexibility inconsideration of mobile reception equipment need to be improved fordigital broadcast.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to an apparatus fortransmitting broadcast signals and an apparatus for receiving broadcastsignals for future broadcast services and methods for transmitting andreceiving broadcast signals for future broadcast services.

An object of the present invention is to provide an apparatus and methodfor transmitting broadcast signals to multiplex data of a broadcasttransmission/reception system providing two or more different broadcastservices in a time domain and transmit the multiplexed data through thesame RF signal bandwidth and an apparatus and method for receivingbroadcast signals corresponding thereto.

Another object of the present invention is to provide an apparatus fortransmitting broadcast signals, an apparatus for receiving broadcastsignals and methods for transmitting and receiving broadcast signals toclassify data corresponding to services by components, transmit datacorresponding to each component as a data pipe, receive and process thedata

Still another object of the present invention is to provide an apparatusfor transmitting broadcast signals, an apparatus for receiving broadcastsignals and methods for transmitting and receiving broadcast signals tosignal signaling information necessary to provide broadcast signals.

Technical Solution

To achieve the object and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, amethod for receiving broadcast signals, the method comprises receivingthe broadcast signals, demodulating the received broadcast signals by anOFDM (Orthogonal Frequency Division Multiplex) scheme, frequencyde-interleaving the demodulated broadcast signals by using a differentinterleaving sequence, wherein the different interleaving sequence isused for data corresponding to an OFDM symbol pair or data correspondingto an OFDM symbol according to an FFT size of the demodulating, parsingat least one signal frame from the frequency de-interleaved broadcastsignals and decoding service data in the parsed at least one signalframe.

Advantageous Effects

The present invention can process data according to servicecharacteristics to control QoS (Quality of Services) for each service orservice component, thereby providing various broadcast services.

The present invention can achieve transmission flexibility bytransmitting various broadcast services through the same RF signalbandwidth.

The present invention can improve data transmission efficiency andincrease robustness of transmission/reception of broadcast signals usinga MIMO system.

According to the present invention, it is possible to provide broadcastsignal transmission and reception methods and apparatus capable ofreceiving digital broadcast signals without error even with mobilereception equipment or in an indoor environment.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 illustrates a structure of an apparatus for transmittingbroadcast signals for future broadcast services according to anembodiment of the present invention.

FIG. 2(a) and FIG. 2(b) illustrate an input formatting block accordingto one embodiment of the present invention.

FIG. 3 illustrates an input formatting block according to anotherembodiment of the present invention.

FIG. 4 illustrates an input formatting block according to anotherembodiment of the present invention.

FIG. 5(a) and FIG. 5(b) illustrate a BICM block according to anembodiment of the present invention.

FIG. 6 illustrates a BICM block according to another embodiment of thepresent invention.

FIG. 7 illustrates a frame building block according to one embodiment ofthe present invention.

FIG. 8 illustrates an OFDM generation block according to an embodimentof the present invention.

FIG. 9 illustrates a structure of an apparatus for receiving broadcastsignals for future broadcast services according to an embodiment of thepresent invention.

FIG. 10(a), FIG. 10(b), FIG. 10(c) and FIG. 10(d) illustrate a framestructure according to an embodiment of the present invention.

FIG. 11 illustrates a signaling hierarchy structure of the frameaccording to an embodiment of the present invention.

FIG. 12 illustrates preamble signaling data according to an embodimentof the present invention.

FIG. 13 illustrates PLS1 data according to an embodiment of the presentinvention.

FIG. 14 illustrates PLS2 data according to an embodiment of the presentinvention.

FIG. 15 illustrates PLS2 data according to another embodiment of thepresent invention.

FIG. 16 illustrates a logical structure of a frame according to anembodiment of the present invention.

FIG. 17 illustrates PLS mapping according to an embodiment of thepresent invention.

FIG. 18 illustrates EAC mapping according to an embodiment of thepresent invention.

FIG. 19(a) and FIG. 19(b) illustrate FIC mapping according to anembodiment of the present invention.

FIG. 20(a) and FIG. 20(b) illustrate a type of DP according to anembodiment of the present invention.

FIG. 21(a) and FIG. 21(c) illustrate DP mapping according to anembodiment of the present invention.

FIG. 22 illustrates an FEC structure according to an embodiment of thepresent invention.

FIG. 23 illustrates a bit interleaving according to an embodiment of thepresent invention.

FIG. 24(a) and FIG. 24(b) illustrate a cell-word demultiplexingaccording to an embodiment of the present invention.

FIG. 25(a), FIG. 25(b) and FIG. 25(c) illustrate a time interleavingaccording to an embodiment of the present invention.

FIG. 26(a) and FIG. 26(b) illustrate the basic operation of a twistedrow-column block interleaver according to an embodiment of the presentinvention.

FIG. 27 illustrates an operation of a twisted row-column blockinterleaver according to another embodiment of the present invention.

FIG. 28 illustrates a diagonal-wise reading pattern of a twistedrow-column block interleaver according to an embodiment of the presentinvention.

FIG. 29 illustrates interlaved XFECBLOCKs from each interleaving arrayaccording to an embodiment of the present invention.

FIG. 30 illustrates operation of the frequency interleaver according toan embodiment of the present invention.

FIG. 31 illustrates a frequency deinterleaving process according to anembodiment of the present invention.

FIG. 32 is a view illustrating single-memory deinterleaving for inputsequential OFDM symbols.

FIG. 33 illustrates equations for describing a process for changing aninterleaving sequence within each memory bank, according to anembodiment of the present invention.

FIG. 34(a) and FIG. 34(b) illustrate a symbol offset generator of 8K FFTmode and equations showing operation of the symbol offset generator,according to an embodiment of the present invention.

FIGS. 35(a) and 35(b) illustrate a symbol offset generator of 8K FFTmode and equations showing operation of the symbol offset generator,according to another embodiment of the present invention.

FIG. 36 illustrates a frequency interleaver of 8K FFT mode according toan embodiment of the present invention.

FIG. 37 illustrates equations showing operation of the frequencyinterleaver of 8K FFT mode according to an embodiment of the presentinvention.

FIG. 38 illustrates the logical structure of the frequency interleaverof 8K FFT mode according to an embodiment of the present invention.

FIG. 39 illustrates a frequency interleaver of 8K FFT mode according toanother embodiment of the present invention.

FIG. 40(a) and FIG. 40(b) illustrate bit shuffling of the frequencyinterleaver of 8K FFT mode and equations showing operation of thefrequency interleaver, according to an embodiment of the presentinvention.

FIG. 41(a) and FIG. 41(b) illustrate a symbol offset generator of 16KFFT mode and equations showing operation of the symbol offset generator,according to an embodiment of the present invention.

FIG. 42(a) and FIG. 42(b) illustrate a symbol offset generator of 16KFFT mode and equations showing operation of the symbol offset generator,according to another embodiment of the present invention.

FIG. 43 illustrates a frequency interleaver of 16K FFT mode according toan embodiment of the present invention.

FIG. 44 illustrates equations showing operation of the frequencyinterleaver of 16K FFT mode according to an embodiment of the presentinvention.

FIG. 45 illustrates the logical structure of the frequency interleaverof 16K FFT mode according to an embodiment of the present invention.

FIG. 46 illustrates a frequency interleaver of 16K FFT mode according toanother embodiment of the present invention.

FIG. 47(a) and FIG. 47(b) illustrate bit shuffling of the frequencyinterleaver of 16K FFT mode and equations showing operation of thefrequency interleaver, according to an embodiment of the presentinvention.

FIG. 48(a) and FIG. 48(b) illustrate a symbol offset generator of 32KFFT mode and equations showing operation of the symbol offset generator,according to an embodiment of the present invention.

FIG. 49(a) and FIG. 49(b) illustrate a symbol offset generator of 32KFFT mode and equations showing operation of the symbol offset generator,according to another embodiment of the present invention.

FIG. 50 illustrates a frequency interleaver of 32K FFT mode according toan embodiment of the present invention.

FIG. 51 illustrates equations showing operation of the frequencyinterleaver of 32K FFT mode according to an embodiment of the presentinvention.

FIG. 52 illustrates the logical structure of the frequency interleaverof 32K FFT mode according to an embodiment of the present invention.

FIG. 53 illustrates a frequency interleaver of 32K FFT mode according toanother embodiment of the present invention.

FIG. 54(a) and FIG. 54(b) illustrate bit shuffling of the frequencyinterleaver of 32K FFT mode and equations showing operation of thefrequency interleaver, according to an embodiment of the presentinvention.

FIG. 55 illustrates an equation showing operation of the frequencyinterleaver of 32K FFT mode according to the present invention.

FIG. 56(a) and FIG. 56(b) illustrate equations showing operation of thefrequency interleaver of 16K FFT mode according to the presentinvention. FIG. 57 illustrates an equation showing operation of thefrequency interleaver of 8K FFT mode according to the present invention.

FIG. 58 illustrates equations showing input and output of a frequencyinterleaver based on each FFT mode.

FIG. 59 illustrates a frequency interleaver of 32K FFT mode according toanother embodiment of the present invention.

FIG. 60 illustrates a frequency interleaver of 16K FFT mode according toanother embodiment of the present invention.

FIG. 61 illustrates a frequency interleaver of 8K FFT mode according toanother embodiment of the present invention.

FIG. 62(a), FIG. 62(b), FIG. 62(c) and FIG. 62(d) illustrate wirepermutation tables according to embodiments of the present invention.

FIG. 63 illustrates an equation showing operation of the basicinterleaving sequence generator according to an embodiment of thepresent invention.

FIG. 64 illustrates an equation showing operation of the symbol offsetgenerator according to an embodiment of the present invention.

FIG. 65 illustrates equations showing an interleaving address accordingto an embodiment of the present invention.

FIG. 66 illustrates an equation showing a frequency interleaver of 16KFFT mode according to another embodiment of the present invention.

FIG. 67(a) and FIG. 67(b) illustrate equations showing operation of thefrequency interleaver of 8K FFT mode according to another embodiment ofthe present invention.

FIG. 68 illustrates an equation showing input and output of a frequencyinterleaver based on each FFT mode.

FIG. 69(a) and FIG. 69(b) illustrate equations showing operation of thefrequency interleaver based on an FFT mode according to an embodiment ofthe present invention.

FIG. 70 illustrates an equation showing an interleaving addressaccording to another embodiment of the present invention.

FIG. 71 illustrates a frequency deinterleaving process according to anembodiment of the present invention.

FIG. 72 illustrates the logical structure of a signal frame according toan embodiment of the present invention.

FIG. 73 illustrates the structure of preamble symbols according to anembodiment of the present invention.

FIG. 74 illustrates a frequency interleaving process of preamble symbolsaccording to an embodiment of the present invention.

FIG. 75 illustrates a frequency interleaving process of preamble symbolsaccording to another embodiment of the present invention.

FIG. 76 illustrates the signaling structure of the logical structure ofa signal frame according to an embodiment of the present invention.

FIG. 77(a) and FIG. 77(b) illustrate the structure of payload data of asignal frame according to an embodiment of the present invention.

FIG. 78(a) and FIG. 78(b) illustrate a procedure for processingsingle-FFT-mode signal frames by the broadcast signal receptionapparatus, according to an embodiment of the present invention.

FIG. 79(a) and FIG. 79(b) illustrate a procedure for processingsingle-FFT-mode signal frames by the broadcast signal receptionapparatus, according to another embodiment of the present invention.

FIG. 80(a) and FIG. 80(b) illustrate a procedure for processingmixed-FFT-mode signal frames by the broadcast signal receptionapparatus, according to an embodiment of the present invention.

FIG. 81(a) and FIG. 81(b) illustrate a procedure for processingmixed-FFT-mode signal frames by the broadcast signal receptionapparatus, according to another embodiment of the present invention.

FIG. 82 is a flowchart illustrating a method for receiving broadcastsignals according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. The detailed description, which will be given below withreference to the accompanying drawings, is intended to explain exemplaryembodiments of the present invention, rather than to show the onlyembodiments that can be implemented according to the present invention.The following detailed description includes specific details in order toprovide a thorough understanding of the present invention. However, itwill be apparent to those skilled in the art that the present inventionmay be practiced without such specific details.

Although most terms used in the present invention have been selectedfrom general ones widely used in the art, some terms have beenarbitrarily selected by the applicant and their meanings are explainedin detail in the following description as needed. Thus, the presentinvention should be understood based upon the intended meanings of theterms rather than their simple names or meanings.

The present invention provides apparatuses and methods for transmittingand receiving broadcast signals for future broadcast services. Futurebroadcast services according to an embodiment of the present inventioninclude a terrestrial broadcast service, a mobile broadcast service, aUHDTV service, etc. The present invention may process broadcast signalsfor the future broadcast services through non-MIMO (Multiple InputMultiple Output) or MIMO according to one embodiment. A non-MIMO schemeaccording to an embodiment of the present invention may include a MISO(Multiple Input Single Output) scheme, a SISO (Single Input SingleOutput) scheme, etc.

While MISO or MIMO uses two antennas in the following for convenience ofdescription, the present invention is applicable to systems using two ormore antennas.

The present invention may defines three physical layer (PL)profiles—base, handheld and advanced profiles—each optimized to minimizereceiver complexity while attaining the performance required for aparticular use case. The physical layer (PHY) profiles are subsets ofall configurations that a corresponding receiver should implement.

The three PHY profiles share most of the functional blocks but differslightly in specific blocks and/or parameters. Additional PHY profilescan be defined in the future. For the system evolution, future profilescan also be multiplexed with the existing profiles in a single RFchannel through a future extension frame (FEF). The details of each PHYprofile are described below.

1. Base Profile

The base profile represents a main use case for fixed receiving devicesthat are usually connected to a roof-top antenna. The base profile alsoincludes portable devices that could be transported to a place butbelong to a relatively stationary reception category. Use of the baseprofile could be extended to handheld devices or even vehicular by someimproved implementations, but those use cases are not expected for thebase profile receiver operation.

Target SNR range of reception is from approximately 10 to 20 dB, whichincludes the 15 dB SNR reception capability of the existing broadcastsystem (e.g. ATSC A/53). The receiver complexity and power consumptionis not as critical as in the battery-operated handheld devices, whichwill use the handheld profile. Key system parameters for the baseprofile are listed in below table 1.

TABLE 1 LDPC codeword length 16K, 64K bits Constellation size 4~10 bpcu(bits per channel use) Time de-interleaving memory size ≦2¹⁹ data cellsPilot patterns Pilot pattern for fixed reception FFT size 16K, 32Kpoints

2. Handheld Profile

The handheld profile is designed for use in handheld and vehiculardevices that operate with battery power. The devices can be moving withpedestrian or vehicle speed. The power consumption as well as thereceiver complexity is very important for the implementation of thedevices of the handheld profile. The target SNR range of the handheldprofile is approximately 0 to 10 dB, but can be configured to reachbelow 0 dB when intended for deeper indoor reception.

In addition to low SNR capability, resilience to the Doppler Effectcaused by receiver mobility is the most important performance attributeof the handheld profile. Key system parameters for the handheld profileare listed in the below table 2.

TABLE 2 LDPC codeword length 16K bits Constellation size 2~8 bpcu Timede-interleaving memory size ≦2¹⁸ data cells Pilot patterns Pilotpatterns for mobile and indoor reception FFT size 8K, 16K points

3. Advanced Profile

The advanced profile provides highest channel capacity at the cost ofmore implementation complexity. This profile requires using MIMOtransmission and reception, and UHDTV service is a target use case forwhich this profile is specifically designed. The increased capacity canalso be used to allow an increased number of services in a givenbandwidth, e.g., multiple SDTV or HDTV services.

The target SNR range of the advanced profile is approximately 20 to 30dB. MIMO transmission may initially use existing elliptically-polarizedtransmission equipment, with extension to full-power cross-polarizedtransmission in the future. Key system parameters for the advancedprofile are listed in below table 3.

TABLE 3 LDPC codeword length 16K, 64K bits Constellation size 8~12 bpcuTime de-interleaving memory size ≦2¹⁹ data cells Pilot patterns Pilotpattern for fixed reception FFT size 16K, 32K points

In this case, the base profile can be used as a profile for both theterrestrial broadcast service and the mobile broadcast service. That is,the base profile can be used to define a concept of a profile whichincludes the mobile profile. Also, the advanced profile can be dividedadvanced profile for a base profile with MIMO and advanced profile for ahandheld profile with MIMO. Moreover, the three profiles can be changedaccording to intention of the designer.

The following terms and definitions may apply to the present invention.The following terms and definitions can be changed according to design.

auxiliary stream: sequence of cells carrying data of as yet undefinedmodulation and coding, which may be used for future extensions or asrequired by broadcasters or network operators

base data pipe: data pipe that carries service signaling data

baseband frame (or BBFRAME): set of Kbch bits which form the input toone FEC encoding process (BCH and LDPC encoding)

cell: modulation value that is carried by one carrier of the OFDMtransmission

coded block: LDPC-encoded block of PLS1 data or one of the LDPC-encodedblocks of PLS2 data

data pipe: logical channel in the physical layer that carries servicedata or related metadata, which may carry one or multiple service(s) orservice component(s).

data pipe unit: a basic unit for allocating data cells to a DP in aframe.

data symbol: OFDM symbol in a frame which is not a preamble symbol (theframe signaling symbol and frame edge symbol is included in the datasymbol)

DP_ID: this 8-bit field identifies uniquely a DP within the systemidentified by the SYSTEM_ID

dummy cell: cell carrying a pseudo-random value used to fill theremaining capacity not used for PLS signaling, DPs or auxiliary streams

emergency alert channel: part of a frame that carries EAS informationdata

frame: physical layer time slot that starts with a preamble and endswith a frame edge symbol

frame repetition unit: a set of frames belonging to same or differentphysical layer profile including a FEF, which is repeated eight times ina super-frame

fast information channel: a logical channel in a frame that carries themapping information between a service and the corresponding base DP

FECBLOCK: set of LDPC-encoded bits of a DP data

FFT size: nominal FFT size used for a particular mode, equal to theactive symbol period Ts expressed in cycles of the elementary period T

frame signaling symbol: OFDM symbol with higher pilot density used atthe start of a frame in certain combinations of FFT size, guard intervaland scattered pilot pattern, which carries a part of the PLS data

frame edge symbol: OFDM symbol with higher pilot density used at the endof a frame in certain combinations of FFT size, guard interval andscattered pilot pattern

frame-group: the set of all the frames having the same PHY profile typein a super-frame.

future extension frame: physical layer time slot within the super-framethat could be used for future extension, which starts with a preamble

Futurecast UTB system: proposed physical layer broadcasting system, ofwhich the input is one or more MPEG2-TS or IP or general stream(s) andof which the output is an RF signal

input stream: A stream of data for an ensemble of services delivered tothe end users by the system.

normal data symbol: data symbol excluding the frame signaling symbol andthe frame edge symbol

PHY profile: subset of all configurations that a corresponding receivershould implement

PLS: physical layer signaling data consisting of PLS1 and PLS2

PLS1: a first set of PLS data carried in the FSS symbols having a fixedsize, coding and modulation, which carries basic information about thesystem as well as the parameters needed to decode the PLS2

NOTE: PLS1 data remains constant for the duration of a frame-group.

PLS2: a second set of PLS data transmitted in the FSS symbol, whichcarries more detailed PLS data about the system and the DPs

PLS2 dynamic data: PLS2 data that may dynamically change frame-by-frame

PLS2 static data: PLS2 data that remains static for the duration of aframe-group

preamble signaling data: signaling data carried by the preamble symboland used to identify the basic mode of the system

preamble symbol: fixed-length pilot symbol that carries basic PLS dataand is located in the beginning of a frame

NOTE: The preamble symbol is mainly used for fast initial band scan todetect the system signal, its timing, frequency offset, and FFT-size.

reserved for future use: not defined by the present document but may bedefined in future

super-frame: set of eight frame repetition units

time interleaving block (TI block): set of cells within which timeinterleaving is carried out, corresponding to one use of the timeinterleaver memory

TI group: unit over which dynamic capacity allocation for a particularDP is carried out, made up of an integer, dynamically varying number ofXFECBLOCKs

NOTE: The TI group may be mapped directly to one frame or may be mappedto multiple frames. It may contain one or more TI blocks.

Type 1 DP: DP of a frame where all DPs are mapped into the frame in TDMfashion

Type 2 DP: DP of a frame where all DPs are mapped into the frame in FDMfashion

XFECBLOCK: set of Ncells cells carrying all the bits of one LDPCFECBLOCK

FIG. 1 illustrates a structure of an apparatus for transmittingbroadcast signals for future broadcast services according to anembodiment of the present invention.

The apparatus for transmitting broadcast signals for future broadcastservices according to an embodiment of the present invention can includean input formatting block 1000, a BICM (Bit interleaved coding &modulation) block 1010, a frame building block 1020, an OFDM (OrthogonalFrequency Division Multiplexing) generation block 1030 and a signalinggeneration block 1040. A description will be given of the operation ofeach module of the apparatus for transmitting broadcast signals.

IP stream/packets and MPEG2-TS are the main input formats, other streamtypes are handled as General Streams. In addition to these data inputs,Management Information is input to control the scheduling and allocationof the corresponding bandwidth for each input stream. One or multiple TSstream(s), IP stream(s) and/or General Stream(s) inputs aresimultaneously allowed.

The input formatting block 1000 can demultiplex each input stream intoone or multiple data pipe(s), to each of which an independent coding andmodulation is applied. The data pipe (DP) is the basic unit forrobustness control, thereby affecting quality-of-service (QoS). One ormultiple service(s) or service component(s) can be carried by a singleDP. Details of operations of the input formatting block 1000 will bedescribed later.

The data pipe is a logical channel in the physical layer that carriesservice data or related metadata, which may carry one or multipleservice(s) or service component(s).

Also, the data pipe unit: a basic unit for allocating data cells to a DPin a frame.

In the BICM block 1010, parity data is added for error correction andthe encoded bit streams are mapped to complex-value constellationsymbols. The symbols are interleaved across a specific interleavingdepth that is used for the corresponding DP. For the advanced profile,MIMO encoding is performed in the BICM block 1010 and the additionaldata path is added at the output for MIMO transmission. Details ofoperations of the BICM block 1010 will be described later.

The Frame Building block 1020 can map the data cells of the input DPsinto the OFDM symbols within a frame. After mapping, the frequencyinterleaving is used for frequency-domain diversity, especially tocombat frequency-selective fading channels. Details of operations of theFrame Building block 1020 will be described later.

After inserting a preamble at the beginning of each frame, the OFDMGeneration block 1030 can apply conventional OFDM modulation having acyclic prefix as guard interval. For antenna space diversity, adistributed MISO scheme is applied across the transmitters. In addition,a Peak-to-Average Power Reduction (PAPR) scheme is performed in the timedomain. For flexible network planning, this proposal provides a set ofvarious FFT sizes, guard interval lengths and corresponding pilotpatterns. Details of operations of the OFDM Generation block 1030 willbe described later.

The Signaling Generation block 1040 can create physical layer signalinginformation used for the operation of each functional block. Thissignaling information is also transmitted so that the services ofinterest are properly recovered at the receiver side. Details ofoperations of the Signaling Generation block 1040 will be describedlater.

FIGS. 2, 3 and 4 illustrate the input formatting block 1000 according toembodiments of the present invention. A description will be given ofeach figure.

FIG. 2 illustrates an input formatting block according to one embodimentof the present invention. FIG. 2 shows an input formatting module whenthe input signal is a single input stream.

The input formatting block illustrated in FIG. 2 corresponds to anembodiment of the input formatting block 1000 described with referenceto FIG. 1.

The input to the physical layer may be composed of one or multiple datastreams Each data stream is carried by one DP. The mode adaptationmodules slice the incoming data stream into data fields of the basebandframe (BBF). The system supports three types of input data streams:MPEG2-TS, Internet protocol (IP) and Generic stream (GS). MPEG2-TS ischaracterized by fixed length (188 byte) packets with the first bytebeing a sync-byte (0x47). An IP stream is composed of variable length IPdatagram packets, as signaled within IP packet headers. The systemsupports both IPv4 and IPv6 for the IP stream. GS may be composed ofvariable length packets or constant length packets, signaled withinencapsulation packet headers.

(a) shows a mode adaptation block 2000 and a stream adaptation 2010 forsignal DP and (b) shows a PLS generation block 2020 and a PLS scrambler2030 for generating and processing PLS data. A description will be givenof the operation of each block.

The Input Stream Splitter splits the input TS, IP, GS streams intomultiple service or service component (audio, video, etc.) streams. Themode adaptation module 2010 is comprised of a CRC Encoder, BB (baseband)Frame Slicer, and BB Frame Header Insertion block.

The CRC Encoder provides three kinds of CRC encoding for error detectionat the user packet (UP) level, i.e., CRC-8, CRC-16, and CRC-32. Thecomputed CRC bytes are appended after the UP. CRC-8 is used for TSstream and CRC-32 for IP stream. If the GS stream doesn't provide theCRC encoding, the proposed CRC encoding should be applied.

BB Frame Slicer maps the input into an internal logical-bit format. Thefirst received bit is defined to be the MSB. The BB Frame Slicerallocates a number of input bits equal to the available data fieldcapacity. To allocate a number of input bits equal to the BBF payload,the UP packet stream is sliced to fit the data field of BBF.

BB Frame Header Insertion block can insert fixed length BBF header of 2bytes is inserted in front of the BB Frame. The BBF header is composedof STUFFI (1 bit), SYNCD (13 bits), and RFU (2 bits). In addition to thefixed 2-Byte BBF header, BBF can have an extension field (1 or 3 bytes)at the end of the 2-byte BBF header.

The stream adaptation 2010 is comprised of stuffing insertion block andBB scrambler.

The stuffing insertion block can insert stuffing field into a payload ofa BB frame. If the input data to the stream adaptation is sufficient tofill a BB-Frame, STUFFI is set to ‘0’ and the BBF has no stuffing field.Otherwise STUFFI is set to ‘1’ and the stuffing field is insertedimmediately after the BBF header. The stuffing field comprises two bytesof the stuffing field header and a variable size of stuffing data.

The BB scrambler scrambles complete BBF for energy dispersal. Thescrambling sequence is synchronous with the BBF. The scrambling sequenceis generated by the feed-back shift register.

The PLS generation block 2020 can generate physical layer signaling(PLS) data. The PLS provides the receiver with a means to accessphysical layer DPs. The PLS data consists of PLS1 data and PLS2 data.

The PLS1 data is a first set of PLS data carried in the FSS symbols inthe frame having a fixed size, coding and modulation, which carriesbasic information about the system as well as the parameters needed todecode the PLS2 data. The PLS1 data provides basic transmissionparameters including parameters required to enable the reception anddecoding of the PLS2 data. Also, the PLS1 data remains constant for theduration of a frame-group.

The PLS2 data is a second set of PLS data transmitted in the FSS symbol,which carries more detailed PLS data about the system and the DPs. ThePLS2 contains parameters that provide sufficient information for thereceiver to decode the desired DP. The PLS2 signaling further consistsof two types of parameters, PLS2 Static data (PLS2-STAT data) and PLS2dynamic data (PLS2-DYN data). The PLS2 Static data is PLS2 data thatremains static for the duration of a frame-group and the PLS2 dynamicdata is PLS2 data that may dynamically change frame-by-frame.

Details of the PLS data will be described later.

The PLS scrambler 2030 can scramble the generated PLS data for energydispersal.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 3 illustrates an input formatting block according to anotherembodiment of the present invention.

The input formatting block illustrated in FIG. 3 corresponds to anembodiment of the input formatting block 1000 described with referenceto FIG. 1.

FIG. 3 shows a mode adaptation block of the input formatting block whenthe input signal corresponds to multiple input streams.

The mode adaptation block of the input formatting block for processingthe multiple input streams can independently process the multiple inputstreams

Referring to FIG. 3, the mode adaptation block for respectivelyprocessing the multiple input streams can include an input streamsplitter 3000, an input stream synchronizer 3010, a compensating delayblock 3020, a null packet deletion block 3030, a head compression block3040, a CRC encoder 3050, a BB frame slicer 3060 and a BB headerinsertion block 3070. Description will be given of each block of themode adaptation block.

Operations of the CRC encoder 3050, BB frame slicer 3060 and BB headerinsertion block 3070 correspond to those of the CRC encoder, BB frameslicer and BB header insertion block described with reference to FIG. 2and thus description thereof is omitted.

The input stream splitter 3000 can split the input TS, IP, GS streamsinto multiple service or service component (audio, video, etc.) streams.

The input stream synchronizer 3010 may be referred as ISSY. The ISSY canprovide suitable means to guarantee Constant Bit Rate (CBR) and constantend-to-end transmission delay for any input data format. The ISSY isalways used for the case of multiple DPs carrying TS, and optionallyused for multiple DPs carrying GS streams.

The compensating delay block 3020 can delay the split TS packet streamfollowing the insertion of ISSY information to allow a TS packetrecombining mechanism without requiring additional memory in thereceiver.

The null packet deletion block 3030, is used only for the TS inputstream case. Some TS input streams or split TS streams may have a largenumber of null-packets present in order to accommodate VBR (variablebit-rate) services in a CBR TS stream. In this case, in order to avoidunnecessary transmission overhead, null-packets can be identified andnot transmitted. In the receiver, removed null-packets can bere-inserted in the exact place where they were originally by referenceto a deleted null-packet (DNP) counter that is inserted in thetransmission, thus guaranteeing constant bit-rate and avoiding the needfor time-stamp (PCR) updating.

The head compression block 3040 can provide packet header compression toincrease transmission efficiency for TS or IP input streams Because thereceiver can have a priori information on certain parts of the header,this known information can be deleted in the transmitter.

For Transport Stream, the receiver has a-priori information about thesync-byte configuration (0x47) and the packet length (188 Byte). If theinput TS stream carries content that has only one PID, i.e., for onlyone service component (video, audio, etc.) or service sub-component (SVCbase layer, SVC enhancement layer, MVC base view or MVC dependentviews), TS packet header compression can be applied (optionally) to theTransport Stream. IP packet header compression is used optionally if theinput steam is an IP stream.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 4 illustrates an input formatting block according to anotherembodiment of the present invention.

The input formatting block illustrated in FIG. 4 corresponds to anembodiment of the input formatting block 1000 described with referenceto FIG. 1.

FIG. 4 illustrates a stream adaptation block of the input formattingmodule when the input signal corresponds to multiple input streams.

Referring to FIG. 4, the mode adaptation block for respectivelyprocessing the multiple input streams can include a scheduler 4000, an1-Frame delay block 4010, a stuffing insertion block 4020, an in-bandsignaling 4030, a BB Frame scrambler 4040, a PLS generation block 4050and a PLS scrambler 4060. Description will be given of each block of thestream adaptation block.

Operations of the stuffing insertion block 4020, the BB Frame scrambler4040, the PLS generation block 4050 and the PLS scrambler 4060correspond to those of the stuffing insertion block, BB scrambler, PLSgeneration block and the PLS scrambler described with reference to FIG.2 and thus description thereof is omitted.

The scheduler 4000 can determine the overall cell allocation across theentire frame from the amount of FECBLOCKs of each DP. Including theallocation for PLS, EAC and FIC, the scheduler generate the values ofPLS2-DYN data, which is transmitted as in-band signaling or PLS cell inFSS of the frame. Details of FECBLOCK, EAC and FIC will be describedlater.

The 1-Frame delay block 4010 can delay the input data by onetransmission frame such that scheduling information about the next framecan be transmitted through the current frame for in-band signalinginformation to be inserted into the DPs.

The in-band signaling 4030 can insert un-delayed part of the PLS2 datainto a DP of a frame.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 5 illustrates a BICM block according to an embodiment of thepresent invention.

The BICM block illustrated in FIG. 5 corresponds to an embodiment of theBICM block 1010 described with reference to FIG. 1.

As described above, the apparatus for transmitting broadcast signals forfuture broadcast services according to an embodiment of the presentinvention can provide a terrestrial broadcast service, mobile broadcastservice, UHDTV service, etc.

Since QoS (quality of service) depends on characteristics of a serviceprovided by the apparatus for transmitting broadcast signals for futurebroadcast services according to an embodiment of the present invention,data corresponding to respective services needs to be processed throughdifferent schemes. Accordingly, the a BICM block according to anembodiment of the present invention can independently process DPs inputthereto by independently applying SISO, MISO and MIMO schemes to thedata pipes respectively corresponding to data paths. Consequently, theapparatus for transmitting broadcast signals for future broadcastservices according to an embodiment of the present invention can controlQoS for each service or service component transmitted through each DP.

(a) shows the BICM block shared by the base profile and the handheldprofile and (b) shows the BICM block of the advanced profile.

The BICM block shared by the base profile and the handheld profile andthe BICM block of the advanced profile can include plural processingblocks for processing each DP.

A description will be given of each processing block of the BICM blockfor the base profile and the handheld profile and the BICM block for theadvanced profile.

A processing block 5000 of the BICM block for the base profile and thehandheld profile can include a Data FEC encoder 5010, a bit interleaver5020, a constellation mapper 5030, an SSD (Signal Space Diversity)encoding block 5040 and a time interleaver 5050.

The Data FEC encoder 5010 can perform the FEC encoding on the input BBFto generate FECBLOCK procedure using outer coding (BCH), and innercoding (LDPC). The outer coding (BCH) is optional coding method. Detailsof operations of the Data FEC encoder 5010 will be described later.

The bit interleaver 5020 can interleave outputs of the Data FEC encoder5010 to achieve optimized performance with combination of the LDPC codesand modulation scheme while providing an efficiently implementablestructure. Details of operations of the bit interleaver 5020 will bedescribed later.

The constellation mapper 5030 can modulate each cell word from the bitinterleaver 5020 in the base and the handheld profiles, or cell wordfrom the Cell-word demultiplexer 5010-1 in the advanced profile usingeither QPSK, QAM-16, non-uniform QAM (NUQ-64, NUQ-256, NUQ-1024) ornon-uniform constellation (NUC-16, NUC-64, NUC-256, NUC-1024) to give apower-normalized constellation point, el. This constellation mapping isapplied only for DPs. Observe that QAM-16 and NUQs are square shaped,while NUCs have arbitrary shape. When each constellation is rotated byany multiple of 90 degrees, the rotated constellation exactly overlapswith its original one. This “rotation-sense” symmetric property makesthe capacities and the average powers of the real and imaginarycomponents equal to each other. Both NUQs and NUCs are definedspecifically for each code rate and the particular one used is signaledby the parameter DP_MOD filed in PLS2 data.

The SSD encoding block 5040 can precode cells in two (2D), three (3D),and four (4D) dimensions to increase the reception robustness underdifficult fading conditions.

The time interleaver 5050 can operates at the DP level. The parametersof time interleaving (TI) may be set differently for each DP. Details ofoperations of the time interleaver 5050 will be described later.

A processing block 5000-1 of the BICM block for the advanced profile caninclude the Data FEC encoder, bit interleaver, constellation mapper, andtime interleaver. However, the processing block 5000-1 is distinguishedfrom the processing block 5000 further includes a cell-worddemultiplexer 5010-1 and a MIMO encoding block 5020-1.

Also, the operations of the Data FEC encoder, bit interleaver,constellation mapper, and time interleaver in the processing block5000-1 correspond to those of the Data FEC encoder 5010, bit interleaver5020, constellation mapper 5030, and time interleaver 5050 described andthus description thereof is omitted.

The cell-word demultiplexer 5010-1 is used for the DP of the advancedprofile to divide the single cell-word stream into dual cell-wordstreams for MIMO processing. Details of operations of the cell-worddemultiplexer 5010-1 will be described later.

The MIMO encoding block 5020-1 can processing the output of thecell-word demultiplexer 5010-1 using MIMO encoding scheme. The MIMOencoding scheme was optimized for broadcasting signal transmission. TheMIMO technology is a promising way to get a capacity increase but itdepends on channel characteristics. Especially for broadcasting, thestrong LOS component of the channel or a difference in the receivedsignal power between two antennas caused by different signal propagationcharacteristics makes it difficult to get capacity gain from MIMO. Theproposed MIMO encoding scheme overcomes this problem using arotation-based pre-coding and phase randomization of one of the MIMOoutput signals.

MIMO encoding is intended for a 2×2 MIMO system requiring at least twoantennas at both the transmitter and the receiver. Two MIMO encodingmodes are defined in this proposal; full-rate spatial multiplexing(FR-SM) and full-rate full-diversity spatial multiplexing (FRFD-SM). TheFR-SM encoding provides capacity increase with relatively smallcomplexity increase at the receiver side while the FRFD-SM encodingprovides capacity increase and additional diversity gain with a greatcomplexity increase at the receiver side. The proposed MIMO encodingscheme has no restriction on the antenna polarity configuration.

MIMO processing is required for the advanced profile frame, which meansall DPs in the advanced profile frame are processed by the MIMO encoder.MIMO processing is applied at DP level. Pairs of the ConstellationMapper outputs NUQ (e1,i and e2,i) are fed to the input of the MIMOEncoder. Paired MIMO Encoder output (g1,i and g2,i) is transmitted bythe same carrier k and OFDM symbol 1 of their respective TX antennas.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 6 illustrates a BICM block according to another embodiment of thepresent invention.

The BICM block illustrated in FIG. 6 corresponds to an embodiment of theBICM block 1010 described with reference to FIG. 1.

FIG. 6 illustrates a BICM block for protection of physical layersignaling (PLS), emergency alert channel (EAC) and fast informationchannel (FIC). EAC is a part of a frame that carries EAS informationdata and FIC is a logical channel in a frame that carries the mappinginformation between a service and the corresponding base DP. Details ofthe EAC and FIC will be described later.

Referring to FIG. 6, the BICM block for protection of PLS, EAC and FICcan include a PLS FEC encoder 6000, a bit interleaver 6010 and aconstellation mapper 6020.

Also, the PLS FEC encoder 6000 can include a scrambler, BCHencoding/zero insertion block, LDPC encoding block and LDPC paritypunturing block. Description will be given of each block of the BICMblock.

The PLS FEC encoder 6000 can encode the scrambled PLS 1/2 data, EAC andFIC section.

The scrambler can scramble PLS1 data and PLS2 data before BCH encodingand shortened and punctured LDPC encoding.

The BCH encoding/zero insertion block can perform outer encoding on thescrambled PLS 1/2 data using the shortened BCH code for PLS protectionand insert zero bits after the BCH encoding. For PLS1 data only, theoutput bits of the zero insertion may be permutted before LDPC encoding.

The LDPC encoding block can encode the output of the BCH encoding/zeroinsertion block using LDPC code. To generate a complete coded block,Cldpc, parity bits, Pldpc are encoded systematically from eachzero-inserted PLS information block, Ildpc and appended after it.

C _(ldpc) =[I _(ldpc) P _(ldpc) ]=[i ₀ ,i ₁ , . . . ,i _(K) _(ldpc) ₋₁,p ₀ ,p ₁ , . . . ,p _(N) _(ldpc) _(-K) _(ldpc) ₋₁]  [Math figure 1]

The LDPC code parameters for PLS1 and PLS2 are as following table 4.

TABLE 4 Signal- ing K_(ldpc) code Type K_(sig) K_(bch) N_(bch)_parity(=N_(bch)) N_(ldpc) N_(ldpc)_parity rate Q_(ldpc) PLS1 342 1020 60 10804320 3240 1/4 36 PLS2 <1021 >1020 2100 2160 7200 5040 3/10 56

The LDPC parity punturing block can perform puncturing on the PLS1 dataand PLS2 data.

When shortening is applied to the PLS1 data protection, some LDPC paritybits are punctured after LDPC encoding. Also, for the PLS2 dataprotection, the LDPC parity bits of PLS2 are punctured after LDPCencoding. These punctured bits are not transmitted.

The bit interleaver 6010 can interleave the each shortened and puncturedPLS1 data and PLS2 data.

The constellation mapper 6020 can map the bit ineterlaeved PLS1 data andPLS2 data onto constellations.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 7 illustrates a frame building block according to one embodiment ofthe present invention.

The frame building block illustrated in FIG. 7 corresponds to anembodiment of the frame building block 1020 described with reference toFIG. 1.

Referring to FIG. 7, the frame building block can include a delaycompensation block 7000, a cell mapper 7010 and a frequency interleaver7020. Description will be given of each block of the frame buildingblock.

The delay compensation block 7000 can adjust the timing between the datapipes and the corresponding PLS data to ensure that they are co-timed atthe transmitter end. The PLS data is delayed by the same amount as datapipes are by addressing the delays of data pipes caused by the InputFormatting block and BICM block. The delay of the BICM block is mainlydue to the time interleaver 5050. In-band signaling data carriesinformation of the next TI group so that they are carried one frameahead of the DPs to be signaled. The Delay Compensating block delaysin-band signaling data accordingly.

The cell mapper 7010 can map PLS, EAC, FIC, DPs, auxiliary streams anddummy cells into the active carriers of the OFDM symbols in the frame.The basic function of the cell mapper 7010 is to map data cells producedby the TIs for each of the DPs, PLS cells, and EAC/FIC cells, if any,into arrays of active OFDM cells corresponding to each of the OFDMsymbols within a frame. Service signaling data (such as PSI (programspecific information)/SI) can be separately gathered and sent by a datapipe. The Cell Mapper operates according to the dynamic informationproduced by the scheduler and the configuration of the frame structure.Details of the frame will be described later.

The frequency interleaver 7020 can randomly interleave data cellsreceived from the cell mapper 7010 to provide frequency diversity. Also,the frequency interleaver 7020 can operate on very OFDM symbol paircomprised of two sequential OFDM symbols using a differentinterleaving-seed order to get maximum interleaving gain in a singleframe.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 8 illustrates an OFDM generation block according to an embodimentof the present invention.

The OFDM generation block illustrated in FIG. 8 corresponds to anembodiment of the OFDM generation block 1030 described with reference toFIG. 1.

The OFDM generation block modulates the OFDM carriers by the cellsproduced by the Frame Building block, inserts the pilots, and producesthe time domain signal for transmission. Also, this block subsequentlyinserts guard intervals, and applies PAPR (Peak-to-Average Power Radio)reduction processing to produce the final RF signal.

Referring to FIG. 8, the OFDM generation block can include a pilot andreserved tone insertion block 8000, a 2D-eSFN encoding block 8010, anIFFT (Inverse Fast Fourier Transform) block 8020, a PAPR reduction block8030, a guard interval insertion block 8040, a preamble insertion block8050, other system insertion block 8060 and a DAC block 8070.Description will be given of each block of the frame building block.

The pilot and reserved tone insertion block 8000 can insert pilots andthe reserved tone.

Various cells within the OFDM symbol are modulated with referenceinformation, known as pilots, which have transmitted values known apriori in the receiver. The information of pilot cells is made up ofscattered pilots, continual pilots, edge pilots, FSS (frame signalingsymbol) pilots and FES (frame edge symbol) pilots. Each pilot istransmitted at a particular boosted power level according to pilot typeand pilot pattern. The value of the pilot information is derived from areference sequence, which is a series of values, one for eachtransmitted carrier on any given symbol. The pilots can be used forframe synchronization, frequency synchronization, time synchronization,channel estimation, and transmission mode identification, and also canbe used to follow the phase noise.

Reference information, taken from the reference sequence, is transmittedin scattered pilot cells in every symbol except the preamble, FSS andFES of the frame. Continual pilots are inserted in every symbol of theframe. The number and location of continual pilots depends on both theFFT size and the scattered pilot pattern. The edge carriers are edgepilots in every symbol except for the preamble symbol. They are insertedin order to allow frequency interpolation up to the edge of thespectrum. FSS pilots are inserted in FSS(s) and FES pilots are insertedin FES. They are inserted in order to allow time interpolation up to theedge of the frame.

The system according to an embodiment of the present invention supportsthe SFN network, where distributed MISO scheme is optionally used tosupport very robust transmission mode. The 2D-eSFN is a distributed MISOscheme that uses multiple TX antennas, each of which is located in thedifferent transmitter site in the SFN network.

The 2D-eSFN encoding block 8010 can process a 2D-eSFN processing todistorts the phase of the signals transmitted from multipletransmitters, in order to create both time and frequency diversity inthe SFN configuration. Hence, burst errors due to low flat fading ordeep-fading for a long time can be mitigated.

The IFFT block 8020 can modulate the output from the 2D-eSFN encodingblock 8010 using OFDM modulation scheme. Any cell in the data symbolswhich has not been designated as a pilot (or as a reserved tone) carriesone of the data cells from the frequency interleaver. The cells aremapped to OFDM carriers.

The PAPR reduction block 8030 can perform a PAPR reduction on inputsignal using various PAPR reduction algorithm in the time domain.

The guard interval insertion block 8040 can insert guard intervals andthe preamble insertion block 8050 can insert preamble in front of thesignal. Details of a structure of the preamble will be described later.The other system insertion block 8060 can multiplex signals of aplurality of broadcast transmission/reception systems in the time domainsuch that data of two or more different broadcast transmission/receptionsystems providing broadcast services can be simultaneously transmittedin the same RF signal bandwidth. In this case, the two or more differentbroadcast transmission/reception systems refer to systems providingdifferent broadcast services. The different broadcast services may referto a terrestrial broadcast service, mobile broadcast service, etc. Datarelated to respective broadcast services can be transmitted throughdifferent frames.

The DAC block 8070 can convert an input digital signal into an analogsignal and output the analog signal. The signal output from the DACblock 7800 can be transmitted through multiple output antennas accordingto the physical layer profiles. A Tx antenna according to an embodimentof the present invention can have vertical or horizontal polarity.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions according to design.

FIG. 9 illustrates a structure of an apparatus for receiving broadcastsignals for future broadcast services according to an embodiment of thepresent invention.

The apparatus for receiving broadcast signals for future broadcastservices according to an embodiment of the present invention cancorrespond to the apparatus for transmitting broadcast signals forfuture broadcast services, described with reference to FIG. 1.

The apparatus for receiving broadcast signals for future broadcastservices according to an embodiment of the present invention can includea synchronization & demodulation module 9000, a frame parsing module9010, a demapping & decoding module 9020, an output processor 9030 and asignaling decoding module 9040. A description will be given of operationof each module of the apparatus for receiving broadcast signals.

The synchronization & demodulation module 9000 can receive input signalsthrough m Rx antennas, perform signal detection and synchronization withrespect to a system corresponding to the apparatus for receivingbroadcast signals and carry out demodulation corresponding to a reverseprocedure of the procedure performed by the apparatus for transmittingbroadcast signals.

The frame parsing module 9010 can parse input signal frames and extractdata through which a service selected by a user is transmitted. If theapparatus for transmitting broadcast signals performs interleaving, theframe parsing module 9010 can carry out deinterleaving corresponding toa reverse procedure of interleaving. In this case, the positions of asignal and data that need to be extracted can be obtained by decodingdata output from the signaling decoding module 9040 to restorescheduling information generated by the apparatus for transmittingbroadcast signals.

The demapping & decoding module 9020 can convert the input signals intobit domain data and then deinterleave the same as necessary. Thedemapping & decoding module 9020 can perform demapping for mappingapplied for transmission efficiency and correct an error generated on atransmission channel through decoding. In this case, the demapping &decoding module 9020 can obtain transmission parameters necessary fordemapping and decoding by decoding the data output from the signalingdecoding module 9040.

The output processor 9030 can perform reverse procedures of variouscompression/signal processing procedures which are applied by theapparatus for transmitting broadcast signals to improve transmissionefficiency. In this case, the output processor 9030 can acquirenecessary control information from data output from the signalingdecoding module 9040. The output of the output processor 8300corresponds to a signal input to the apparatus for transmittingbroadcast signals and may be MPEG-TSs, IP streams (v4 or v6) and genericstreams.

The signaling decoding module 9040 can obtain PLS information from thesignal demodulated by the synchronization & demodulation module 9000. Asdescribed above, the frame parsing module 9010, demapping & decodingmodule 9020 and output processor 9030 can execute functions thereofusing the data output from the signaling decoding module 9040.

FIG. 10 illustrates a frame structure according to an embodiment of thepresent invention.

FIG. 10 shows an example configuration of the frame types and FRUs in asuper-frame. (a) shows a super frame according to an embodiment of thepresent invention, (b) shows FRU (Frame Repetition Unit) according to anembodiment of the present invention, (c) shows frames of variable PHYprofiles in the FRU and (d) shows a structure of a frame.

A super-frame may be composed of eight FRUs. The FRU is a basicmultiplexing unit for TDM of the frames, and is repeated eight times ina super-frame.

Each frame in the FRU belongs to one of the PHY profiles, (base,handheld, advanced) or FEF. The maximum allowed number of the frames inthe FRU is four and a given PHY profile can appear any number of timesfrom zero times to four times in the FRU (e.g., base, base, handheld,advanced). PHY profile definitions can be extended using reserved valuesof the PHY_PROFILE in the preamble, if required.

The FEF part is inserted at the end of the FRU, if included. When theFEF is included in the FRU, the minimum number of FEFs is 8 in asuper-frame. It is not recommended that FEF parts be adjacent to eachother.

One frame is further divided into a number of OFDM symbols and apreamble. As shown in (d), the frame comprises a preamble, one or moreframe signaling symbols (FSS), normal data symbols and a frame edgesymbol (FES).

The preamble is a special symbol that enables fast Futurecast UTB systemsignal detection and provides a set of basic transmission parameters forefficient transmission and reception of the signal. The detaileddescription of the preamble will be will be described later.

The main purpose of the FSS(s) is to carry the PLS data. For fastsynchronization and channel estimation, and hence fast decoding of PLSdata, the FSS has more dense pilot pattern than the normal data symbol.The FES has exactly the same pilots as the FSS, which enablesfrequency-only interpolation within the FES and temporal interpolation,without extrapolation, for symbols immediately preceding the FES.

FIG. 11 illustrates a signaling hierarchy structure of the frameaccording to an embodiment of the present invention.

FIG. 11 illustrates the signaling hierarchy structure, which is splitinto three main parts: the preamble signaling data 11000, the PLS1 data11010 and the PLS2 data 11020. The purpose of the preamble, which iscarried by the preamble symbol in every frame, is to indicate thetransmission type and basic transmission parameters of that frame. ThePLS1 enables the receiver to access and decode the PLS2 data, whichcontains the parameters to access the DP of interest. The PLS2 iscarried in every frame and split into two main parts: PLS2-STAT data andPLS2-DYN data. The static and dynamic portion of PLS2 data is followedby padding, if necessary.

FIG. 12 illustrates preamble signaling data according to an embodimentof the present invention.

Preamble signaling data carries 21 bits of information that are neededto enable the receiver to access PLS data and trace DPs within the framestructure. Details of the preamble signaling data are as follows:

PHY_PROFILE: This 3-bit field indicates the PHY profile type of thecurrent frame. The mapping of different PHY profile types is given inbelow table 5.

TABLE 5 Value PHY profile 000 Base profile 001 Handheld profile 010Advanced profiled 011~110 Reserved 111 FEF

FFT_SIZE: This 2 bit field indicates the FFT size of the current framewithin a frame-group, as described in below table 6.

TABLE 6 Value FFT size 00 8K FFT 01 16K FFT 10 32K FFT 11 Reserved

GI_FRACTION: This 3 bit field indicates the guard interval fractionvalue in the current super-frame, as described in below table 7.

TABLE 7 Value GI_FRACTION 000 1/5  001 1/10 010 1/20 011 1/40 100 1/80101  1/160 110~111 Reserved

EAC_FLAG: This 1 bit field indicates whether the EAC is provided in thecurrent frame. If this field is set to ‘1’, emergency alert service(EAS) is provided in the current frame. If this field set to ‘0’, EAS isnot carried in the current frame. This field can be switched dynamicallywithin a super-frame.

PILOT_MODE: This 1-bit field indicates whether the pilot mode is mobilemode or fixed mode for the current frame in the current frame-group. Ifthis field is set to ‘0’, mobile pilot mode is used. If the field is setto ‘1’, the fixed pilot mode is used.

PAPR_FLAG: This 1-bit field indicates whether PAPR reduction is used forthe current frame in the current frame-group. If this field is set tovalue ‘1’, tone reservation is used for PAPR reduction. If this field isset to ‘0’, PAPR reduction is not used.

FRU_CONFIGURE: This 3-bit field indicates the PHY profile typeconfigurations of the frame repetition units (FRU) that are present inthe current super-frame. All profile types conveyed in the currentsuper-frame are identified in this field in all preambles in the currentsuper-frame. The 3-bit field has a different definition for eachprofile, as show in below table 8.

TABLE 8 Current Current Current Current PHY_PRO- PHY_PRO- PHY_PRO-PHY_PRO- FILE = FILE FILE FILE = ‘000’ ‘001’ ‘010’ ‘111’ (base)(handheld) (advanced) (FEF) FRU_CON- Only base Only Only Only FEF FIGURE= profile handheld advanced present 000 present profile profile presentpresent FRU_CON- Handheld Base Base Base FIGURE = profile profileprofile profile 1XX present present present present FRU_CON- AdvancedAdvanced Handheld Handheld FIGURE = profile profile profile profile X1Xpresent present present present FRU_CON- FEF FEF FEF Advanced FIGURE =present present present profile XX1 present

RESERVED: This 7-bit field is reserved for future use.

FIG. 13 illustrates PLS1 data according to an embodiment of the presentinvention.

PLS1 data provides basic transmission parameters including parametersrequired to enable the reception and decoding of the PLS2. As abovementioned, the PLS1 data remain unchanged for the entire duration of oneframe-group. The detailed definition of the signaling fields of the PLS1data are as follows:

PREAMBLE_DATA: This 20-bit field is a copy of the preamble signalingdata excluding the EAC_FLAG.

NUM_FRAME_FRU: This 2-bit field indicates the number of the frames perFRU.

PAYLOAD_TYPE: This 3-bit field indicates the format of the payload datacarried in the frame-group. PAYLOAD_TYPE is signaled as shown in table9.

TABLE 9 value Payload type 1XX TS stream is transmitted X1X IP stream istransmitted XX1 GS stream is transmitted

NUM_FSS: This 2-bit field indicates the number of FSS symbols in thecurrent frame.

SYSTEM_VERSION: This 8-bit field indicates the version of thetransmitted signal format. The SYSTEM_VERSION is divided into two 4-bitfields, which are a major version and a minor version.

Major version: The MSB four bits of SYSTEM_VERSION field indicate majorversion information. A change in the major version field indicates anon-backward-compatible change. The default value is ‘0000’. For theversion described in this standard, the value is set to ‘0000’.

Minor version: The LSB four bits of SYSTEM_VERSION field indicate minorversion information. A change in the minor version field isbackward-compatible.

CELL_ID: This is a 16-bit field which uniquely identifies a geographiccell in an ATSC network. An ATSC cell coverage area may consist of oneor more frequencies, depending on the number of frequencies used perFuturecast UTB system. If the value of the CELL_ID is not known orunspecified, this field is set to ‘0’.

NETWORK_ID: This is a 16-bit field which uniquely identifies the currentATSC network.

SYSTEM_ID: This 16-bit field uniquely identifies the Futurecast UTBsystem within the ATSC network. The Futurecast UTB system is theterrestrial broadcast system whose input is one or more input streams(TS, IP, GS) and whose output is an RF signal. The Futurecast UTB systemcarries one or more PHY profiles and FEF, if any. The same FuturecastUTB system may carry different input streams and use different RFfrequencies in different geographical areas, allowing local serviceinsertion. The frame structure and scheduling is controlled in one placeand is identical for all transmissions within a Futurecast UTB system.One or more Futurecast UTB systems may have the same SYSTEM_ID meaningthat they all have the same physical layer structure and configuration.

The following loop consists of FRU_PHY_PROFILE, FRU_FRAME_LENGTH,FRU_GI_FRACTION, and RESERVED which are used to indicate the FRUconfiguration and the length of each frame type. The loop size is fixedso that four PHY profiles (including a FEF) are signaled within the FRU.If NUM_FRAME_FRU is less than 4, the unused fields are filled withzeros.

FRU_PHY_PROFILE: This 3-bit field indicates the PHY profile type of the(i+1)th (i is the loop index) frame of the associated FRU. This fielduses the same signaling format as shown in the table 8.

FRU_FRAME_LENGTH: This 2-bit field indicates the length of the (i+1)thframe of the associated FRU. Using FRU_FRAME_LENGTH together withFRU_GI_FRACTION, the exact value of the frame duration can be obtained.

FRU_GI_FRACTION: This 3-bit field indicates the guard interval fractionvalue of the (i+1)th frame of the associated FRU. FRU_GI_FRACTION issignaled according to the table 7.

RESERVED: This 4-bit field is reserved for future use.

The following fields provide parameters for decoding the PLS2 data.

PLS2_FEC_TYPE: This 2-bit field indicates the FEC type used by the PLS2protection. The FEC type is signaled according to table 10. The detailsof the LDPC codes will be described later.

TABLE 10 Content PLS2 FEC type 00 4K-1/4 and 7K-3/10 LDPC codes 01~11Reserved

PLS2_MOD: This 3-bit field indicates the modulation type used by thePLS2. The modulation type is signaled according to table 11.

TABLE 11 Value PLS2_MODE 000 BPSK 001 QPSK 010 QAM-16 011 NUQ-64 100~111Reserved

PLS2_SIZE_CELL: This 15-bit field indicates Ctotal_partial_block, thesize (specified as the number of QAM cells) of the collection of fullcoded blocks for PLS2 that is carried in the current frame-group. Thisvalue is constant during the entire duration of the current frame-group.

PLS2_STAT_SIZE_BIT: This 14-bit field indicates the size, in bits, ofthe PLS2-STAT for the current frame-group. This value is constant duringthe entire duration of the current frame-group.

PLS2_DYN_SIZE_BIT: This 14-bit field indicates the size, in bits, of thePLS2-DYN for the current frame-group. This value is constant during theentire duration of the current frame-group.

PLS2_REP_FLAG: This 1-bit flag indicates whether the PLS2 repetitionmode is used in the current frame-group. When this field is set to value‘1’, the PLS2 repetition mode is activated. When this field is set tovalue ‘0’, the PLS2 repetition mode is deactivated.

PLS2_REP_SIZE_CELL: This 15-bit field indicates Ctotal_partial_block,the size (specified as the number of QAM cells) of the collection ofpartial coded blocks for PLS2 carried in every frame of the currentframe-group, when PLS2 repetition is used. If repetition is not used,the value of this field is equal to 0. This value is constant during theentire duration of the current frame-group.

PLS2_NEXT_FEC_TYPE: This 2-bit field indicates the FEC type used forPLS2 that is carried in every frame of the next frame-group. The FECtype is signaled according to the table 10.

PLS2_NEXT_MOD: This 3-bit field indicates the modulation type used forPLS2 that is carried in every frame of the next frame-group. Themodulation type is signaled according to the table 11.

PLS2_NEXT_REP_FLAG: This 1-bit flag indicates whether the PLS2repetition mode is used in the next frame-group. When this field is setto value ‘1’, the PLS2 repetition mode is activated. When this field isset to value ‘0’, the PLS2 repetition mode is deactivated.

PLS2_NEXT_REP_SIZE_CELL: This 15-bit field indicates Ctotal_full_block,The size (specified as the number of QAM cells) of the collection offull coded blocks for PLS2 that is carried in every frame of the nextframe-group, when PLS2 repetition is used. If repetition is not used inthe next frame-group, the value of this field is equal to 0. This valueis constant during the entire duration of the current frame-group.

PLS2_NEXT_REP_STAT_SIZE_BIT: This 14-bit field indicates the size, inbits, of the PLS2-STAT for the next frame-group. This value is constantin the current frame-group.

PLS2_NEXT_REP_DYN_SIZE_BIT: This 14-bit field indicates the size, inbits, of the PLS2-DYN for the next frame-group. This value is constantin the current frame-group.

PLS2_AP_MODE: This 2-bit field indicates whether additional parity isprovided for PLS2 in the current frame-group. This value is constantduring the entire duration of the current frame-group. The below table12 gives the values of this field. When this field is set to ‘00’,additional parity is not used for the PLS2 in the current frame-group.

TABLE 12 Value PLS2-AP mode 00 AP is not provided 01 AP1 mode 10~11Reserved

PLS2_AP_SIZE_CELL: This 15-bit field indicates the size (specified asthe number of QAM cells) of the additional parity bits of the PLS2. Thisvalue is constant during the entire duration of the current frame-group.

PLS2_NEXT_AP_MODE: This 2-bit field indicates whether additional parityis provided for PLS2 signaling in every frame of next frame-group. Thisvalue is constant during the entire duration of the current frame-group.The table 12 defines the values of this field

PLS2_NEXT_AP_SIZE_CELL: This 15-bit field indicates the size (specifiedas the number of QAM cells) of the additional parity bits of the PLS2 inevery frame of the next frame-group. This value is constant during theentire duration of the current frame-group.

RESERVED: This 32-bit field is reserved for future use.

CRC_32: A 32-bit error detection code, which is applied to the entirePLS1 signaling.

FIG. 14 illustrates PLS2 data according to an embodiment of the presentinvention.

FIG. 14 illustrates PLS2-STAT data of the PLS2 data. The PLS2-STAT dataare the same within a frame-group, while the PLS2-DYN data provideinformation that is specific for the current frame.

The details of fields of the PLS2-STAT data are as follows:

FIC_FLAG: This 1-bit field indicates whether the FIC is used in thecurrent frame-group. If this field is set to ‘1’, the FIC is provided inthe current frame. If this field set to ‘0’, the FIC is not carried inthe current frame. This value is constant during the entire duration ofthe current frame-group.

AUX_FLAG: This 1-bit field indicates whether the auxiliary stream(s) isused in the current frame-group. If this field is set to ‘1’, theauxiliary stream is provided in the current frame. If this field set to‘0’, the auxiliary stream is not carried in the current frame. Thisvalue is constant during the entire duration of current frame-group.

NUM_DP: This 6-bit field indicates the number of DPs carried within thecurrent frame. The value of this field ranges from 1 to 64, and thenumber of DPs is NUM_DP+1.

DP_ID: This 6-bit field identifies uniquely a DP within a PHY profile.

DP_TYPE: This 3-bit field indicates the type of the DP. This is signaledaccording to the below table 13.

TABLE 13 Value DP Type 000 DP Type 1 001 DP Type 2 010~111 reserved

DP_GROUP_ID: This 8-bit field identifies the DP group with which thecurrent DP is associated. This can be used by a receiver to access theDPs of the service components associated with a particular service,which will have the same DP_GROUP_ID.

BASE_DP_ID: This 6-bit field indicates the DP carrying service signalingdata (such as PSI/SI) used in the Management layer. The DP indicated byBASE_DP_ID may be either a normal DP carrying the service signaling dataalong with the service data or a dedicated DP carrying only the servicesignaling data

DP_FEC_TYPE: This 2-bit field indicates the FEC type used by theassociated DP. The FEC type is signaled according to the below table 14.

TABLE 14 Value FEC_TYPE 00 16K LDPC 01 64K LDPC 10~11 Reserved

DP_COD: This 4-bit field indicates the code rate used by the associatedDP. The code rate is signaled according to the below table 15.

TABLE 15 Value Code rate 0000 5/15 0001 6/15 0010 7/15 0011 8/15 01009/15 0101 10/15  0110 11/15  0111 12/15  1000 13/15  1001~1111 Reserved

DP_MOD: This 4-bit field indicates the modulation used by the associatedDP. The modulation is signaled according to the below table 16.

TABLE 16 Value Modulation 0000 QPSK 0001 QAM-16 0010 NUQ-64 0011 NUQ-2560100 NUQ-1024 0101 NUC-16 0110 NUC-64 0111 NUC-256 1000 NUC-10241001~1111 reserved

DP_(—) SSD_FLAG: This 1-bit field indicates whether the SSD mode is usedin the associated DP. If this field is set to value ‘1’, SSD is used. Ifthis field is set to value ‘0’, SSD is not used.

The following field appears only if PHY_PROFILE is equal to ‘010’, whichindicates the advanced profile:

DP_MIMO: This 3-bit field indicates which type of MIMO encoding processis applied to the associated DP. The type of MIMO encoding process issignaled according to the table 17.

TABLE 17 Value MIMO encoding 000 FR-SM 001 FRFD-SM 010~111 reserved

DP_TI_TYPE: This 1-bit field indicates the type of time-interleaving. Avalue of ‘0’ indicates that one TI group corresponds to one frame andcontains one or more TI-blocks. A value of ‘1’ indicates that one TIgroup is carried in more than one frame and contains only one TI-block.

DP_TI_LENGTH: The use of this 2-bit field (the allowed values are only1, 2, 4, 8) is determined by the values set within the DP_TI_TYPE fieldas follows:

If the DP_TI_TYPE is set to the value ‘1’, this field indicates PI, thenumber of the frames to which each TI group is mapped, and there is oneTI-block per TI group (NTI=1). The allowed PI values with 2-bit fieldare defined in the below table 18.

If the DP_TI_TYPE is set to the value ‘0’, this field indicates thenumber of TI-blocks NTI per TI group, and there is one TI group perframe (PI=1). The allowed PI values with 2-bit field are defined in thebelow table 18.

TABLE 18 2-bit field P_(I) N_(TI) 00 1 1 01 2 2 10 4 3 11 8 4

DP_FRAME_INTERVAL: This 2-bit field indicates the frame interval (IJUMP)within the frame-group for the associated DP and the allowed values are1, 2, 4, 8 (the corresponding 2-bit field is ‘00’, ‘01’, ‘10’, or ‘11’,respectively). For DPs that do not appear every frame of theframe-group, the value of this field is equal to the interval betweensuccessive frames. For example, if a DP appears on the frames 1, 5, 9,13, etc., this field is set to ‘4’. For DPs that appear in every frame,this field is set to ‘1’.

DP_TI_BYPASS: This 1-bit field determines the availability of timeinterleaver 5050. If time interleaving is not used for a DP, it is setto ‘1’. Whereas if time interleaving is used it is set to ‘0’.

DP_FIRST_FRAME_IDX: This 5-bit field indicates the index of the firstframe of the super-frame in which the current DP occurs. The value ofDP_FIRST_FRAME_IDX ranges from 0 to 31

DP_NUM_BLOCK_MAX: This 10-bit field indicates the maximum value ofDP_NUM_BLOCKS for this DP. The value of this field has the same range asDP_NUM_BLOCKS.

DP_PAYLOAD_TYPE: This 2-bit field indicates the type of the payload datacarried by the given DP. DP_PAYLOAD_TYPE is signaled according to thebelow table 19.

TABLE 19 Value Payload Type 00 TS. 01 IP 10 GS 11 reserved

DP_INBAND_MODE: This 2-bit field indicates whether the current DPcarries in-band signaling information. The in-band signaling type issignaled according to the below table 20.

TABLE 20 Value In-band mode 00 In-band signaling is not carried. 01INBAND-PLS is carried only 10 INBAND-ISSY is carried only 11 INBAND-PLSand INBAND-ISSY are carried

DP_PROTOCOL_TYPE: This 2-bit field indicates the protocol type of thepayload carried by the given DP. It is signaled according to the belowtable 21 when input payload types are selected.

TABLE 21 If DP_PAY- If DP_PAY- If DP_PAY- LOAD_TYPE LOAD_TYPE LOAD_TYPEValue Is TS Is IP Is GS 00 MPEG2-TS IPv4 (Note) 01 Reserved IPv6Reserved 10 Reserved Reserved Reserved 11 Reserved Reserved Reserved

DP_CRC_MODE: This 2-bit field indicates whether CRC encoding is used inthe Input Formatting block. The CRC mode is signaled according to thebelow table 22.

TABLE 22 Value CRC mode 00 Not used 01 CRC-8 10 CRC-16 11 CRC-32

DNP_MODE: This 2-bit field indicates the null-packet deletion mode usedby the associated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). DNP_MODEis signaled according to the below table 23. If DP_PAYLOAD_TYPE is notTS (‘00’), DNP_MODE is set to the value ‘00’.

TABLE 23 Value Null-packet deletion mode 00 Not used 01 DNP-NORMAL 10DNP-OFFSET 11 reserved

ISSY_MODE: This 2-bit field indicates the ISSY mode used by theassociated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). The ISSY_MODE issignaled according to the below table 24 If DP_PAYLOAD_TYPE is not TS(‘00’), ISSY_MODE is set to the value ‘00’.

TABLE 24 Value ISSY mode 00 Not used 01 ISSY-UP 10 ISSY-BBF 11 reserved

HC_MODE_TS: This 2-bit field indicates the TS header compression modeused by the associated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). TheHC_MODE_TS is signaled according to the below table 25.

TABLE 25 Value Header compression mode 00 HC_MODE_TS 1 01 HC_MODE_TS 210 HC_MODE_TS 3 11 HC_MODE_TS 4HC_MODE_IP: This 2-bit field indicates the IP header compression modewhen DP_PAYLOAD_TYPE is set to IP (‘01’). The HC_MODE_TP is signaledaccording to the below table 26.

TABLE 26 Value Header compression mode 00 No compression 01 HC_MODE_IP 110~11 reserved

PID: This 13-bit field indicates the PID number for TS headercompression when DP_PAYLOAD_TYPE is set to TS (‘00’) and HC_MODE_TS isset to ‘01’ or ‘10’.

RESERVED: This 8-bit field is reserved for future use.

The following field appears only if FIC_FLAG is equal to ‘1’:

FIC_VERSION: This 8-bit field indicates the version number of the FIC.

FIC_LENGTH_BYTE: This 13-bit field indicates the length, in bytes, ofthe FIC.

RESERVED: This 8-bit field is reserved for future use.

The following field appears only if AUX_FLAG is equal to ‘1’:

NUM_AUX: This 4-bit field indicates the number of auxiliary streams Zeromeans no auxiliary streams are used.

AUX_CONFIG_RFU: This 8-bit field is reserved for future use.

AUX_STREAM_TYPE: This 4-bit is reserved for future use for indicatingthe type of the current auxiliary stream.

AUX_PRIVATE_CONFIG: This 28-bit field is reserved for future use forsignaling auxiliary streams

FIG. 15 illustrates PLS2 data according to another embodiment of thepresent invention.

FIG. 15 illustrates PLS2-DYN data of the PLS2 data. The values of thePLS2-DYN data may change during the duration of one frame-group, whilethe size of fields remains constant.

The details of fields of the PLS2-DYN data are as follows:

FRAME_INDEX: This 5-bit field indicates the frame index of the currentframe within the super-frame. The index of the first frame of thesuper-frame is set to ‘0’.

PLS_CHANGE_COUNTER: This 4-bit field indicates the number ofsuper-frames ahead where the configuration will change. The nextsuper-frame with changes in the configuration is indicated by the valuesignaled within this field. If this field is set to the value ‘0000’, itmeans that no scheduled change is foreseen: e.g., value ‘1’ indicatesthat there is a change in the next super-frame.

FIC_CHANGE_COUNTER: This 4-bit field indicates the number ofsuper-frames ahead where the configuration (i.e., the contents of theFIC) will change. The next super-frame with changes in the configurationis indicated by the value signaled within this field. If this field isset to the value ‘0000’, it means that no scheduled change is foreseen:e.g. value ‘0001’ indicates that there is a change in the nextsuper-frame.

RESERVED: This 16-bit field is reserved for future use.

The following fields appear in the loop over NUM_DP, which describe theparameters associated with the DP carried in the current frame.

DP_ID: This 6-bit field indicates uniquely the DP within a PHY profile.

DP_START: This 15-bit (or 13-bit) field indicates the start position ofthe first of the DPs using the DPU addressing scheme. The DP_START fieldhas differing length according to the PHY profile and FFT size as shownin the below table 27.

TABLE 27 DP_START field size PHY profile 64K 16K Base 13 bit 15 bitHandheld — 13 bit Advanced 13 bit 15 bit

DP_NUM_BLOCK: This 10-bit field indicates the number of FEC blocks inthe current TI group for the current DP. The value of DP_NUM_BLOCKranges from 0 to 1023

RESERVED: This 8-bit field is reserved for future use.

The following fields indicate the FIC parameters associated with theEAC.

EAC_FLAG: This 1-bit field indicates the existence of the EAC in thecurrent frame. This bit is the same value as the EAC_FLAG in thepreamble.

EAS_WAKE_UP_VERSION_NUM: This 8-bit field indicates the version numberof a wake-up indication.

If the EAC_FLAG field is equal to ‘1’, the following 12 bits areallocated for EAC_LENGTH_BYTE field. If the EAC_FLAG field is equal to‘0’, the following 12 bits are allocated for EAC_COUNTER.

EAC_LENGTH_BYTE: This 12-bit field indicates the length, in byte, of theEAC.

EAC_COUNTER: This 12-bit field indicates the number of the frames beforethe frame where the EAC arrives.

The following field appears only if the AUX_FLAG field is equal to ‘1’:

AUX_PRIVATE_DYN: This 48-bit field is reserved for future use forsignaling auxiliary streams. The meaning of this field depends on thevalue of AUX_STREAM_TYPE in the configurable PLS2-STAT.

CRC_32: A 32-bit error detection code, which is applied to the entirePLS2.

FIG. 16 illustrates a logical structure of a frame according to anembodiment of the present invention.

As above mentioned, the PLS, EAC, FIC, DPs, auxiliary streams and dummycells are mapped into the active carriers of the OFDM symbols in theframe. The PLS1 and PLS2 are first mapped into one or more FSS(s). Afterthat, EAC cells, if any, are mapped immediately following the PLS field,followed next by FIC cells, if any. The DPs are mapped next after thePLS or EAC, FIC, if any. Type 1 DPs follows first, and Type 2 DPs next.The details of a type of the DP will be described later. In some case,DPs may carry some special data for EAS or service signaling data. Theauxiliary stream or streams, if any, follow the DPs, which in turn arefollowed by dummy cells. Mapping them all together in the abovementioned order, i.e. PLS, EAC, FIC, DPs, auxiliary streams and dummydata cells exactly fill the cell capacity in the frame.

FIG. 17 illustrates PLS mapping according to an embodiment of thepresent invention.

PLS cells are mapped to the active carriers of FSS(s). Depending on thenumber of cells occupied by PLS, one or more symbols are designated asFSS(s), and the number of FSS(s) NFSS is signaled by NUM_FSS in PLS1.The FSS is a special symbol for carrying PLS cells. Since robustness andlatency are critical issues in the PLS, the FSS(s) has higher density ofpilots allowing fast synchronization and frequency-only interpolationwithin the FSS.

PLS cells are mapped to active carriers of the NFSS FSS(s) in a top-downmanner as shown in an example in FIG. 17. The PLS1 cells are mappedfirst from the first cell of the first FSS in an increasing order of thecell index. The PLS2 cells follow immediately after the last cell of thePLS1 and mapping continues downward until the last cell index of thefirst FSS. If the total number of required PLS cells exceeds the numberof active carriers of one FSS, mapping proceeds to the next FSS andcontinues in exactly the same manner as the first FSS.

After PLS mapping is completed, DPs are carried next. If EAC, FIC orboth are present in the current frame, they are placed between PLS and“normal” DPs.

FIG. 18 illustrates EAC mapping according to an embodiment of thepresent invention.

EAC is a dedicated channel for carrying EAS messages and links to theDPs for EAS. EAS support is provided but EAC itself may or may not bepresent in every frame. EAC, if any, is mapped immediately after thePLS2 cells. EAC is not preceded by any of the FIC, DPs, auxiliarystreams or dummy cells other than the PLS cells. The procedure ofmapping the EAC cells is exactly the same as that of the PLS.

The EAC cells are mapped from the next cell of the PLS2 in increasingorder of the cell index as shown in the example in FIG. 18. Depending onthe EAS message size, EAC cells may occupy a few symbols, as shown inFIG. 18.

EAC cells follow immediately after the last cell of the PLS2, andmapping continues downward until the last cell index of the last FSS. Ifthe total number of required EAC cells exceeds the number of remainingactive carriers of the last FSS mapping proceeds to the next symbol andcontinues in exactly the same manner as FSS(s). The next symbol formapping in this case is the normal data symbol, which has more activecarriers than a FSS.

After EAC mapping is completed, the FIC is carried next, if any exists.If FIC is not transmitted (as signaled in the PLS2 field), DPs followimmediately after the last cell of the EAC.

FIG. 19 illustrates FIC mapping according to an embodiment of thepresent invention.

shows an example mapping of FIC cell without EAC and (b) shows anexample mapping of FIC cell with EAC.

FIC is a dedicated channel for carrying cross-layer information toenable fast service acquisition and channel scanning. This informationprimarily includes channel binding information between DPs and theservices of each broadcaster. For fast scan, a receiver can decode FICand obtain information such as broadcaster ID, number of services, andBASE_DP_ID. For fast service acquisition, in addition to FIC, base DPcan be decoded using BASE_DP_ID. Other than the content it carries, abase DP is encoded and mapped to a frame in exactly the same way as anormal DP. Therefore, no additional description is required for a baseDP. The FIC data is generated and consumed in the Management Layer. Thecontent of FIC data is as described in the Management Layerspecification.

The FIC data is optional and the use of FIC is signaled by the FIC_FLAGparameter in the static part of the PLS2. If FIC is used, FIC_FLAG isset to ‘1’ and the signaling field for FIC is defined in the static partof PLS2. Signaled in this field are FIC_VERSION, and FIC_LENGTH_BYTE.FIC uses the same modulation, coding and time interleaving parameters asPLS2. FIC shares the same signaling parameters such as PLS2_MOD andPLS2_FEC. FIC data, if any, is mapped immediately after PLS2 or EAC ifany. FIC is not preceded by any normal DPs, auxiliary streams or dummycells. The method of mapping FIC cells is exactly the same as that ofEAC which is again the same as PLS.

Without EAC after PLS, FIC cells are mapped from the next cell of thePLS2 in an increasing order of the cell index as shown in an example in(a). Depending on the FIC data size, FIC cells may be mapped over a fewsymbols, as shown in (b).

FIC cells follow immediately after the last cell of the PLS2, andmapping continues downward until the last cell index of the last FSS. Ifthe total number of required FIC cells exceeds the number of remainingactive carriers of the last FSS, mapping proceeds to the next symbol andcontinues in exactly the same manner as FSS(s). The next symbol formapping in this case is the normal data symbol which has more activecarriers than a FSS.

If EAS messages are transmitted in the current frame, EAC precedes FIC,and FIC cells are mapped from the next cell of the EAC in an increasingorder of the cell index as shown in (b).

After FIC mapping is completed, one or more DPs are mapped, followed byauxiliary streams, if any, and dummy cells.

FIG. 20 illustrates a type of DP according to an embodiment of thepresent invention.

shows type 1 DP and (b) shows type 2 DP.

After the preceding channels, i.e., PLS, EAC and FIC, are mapped, cellsof the DPs are mapped. A DP is categorized into one of two typesaccording to mapping method:

Type 1 DP: DP is mapped by TDM

Type 2 DP: DP is mapped by FDM

The type of DP is indicated by DP_TYPE field in the static part of PLS2.FIG. 20 illustrates the mapping orders of Type 1 DPs and Type 2 DPs.Type 1 DPs are first mapped in the increasing order of cell index, andthen after reaching the last cell index, the symbol index is increasedby one. Within the next symbol, the DP continues to be mapped in theincreasing order of cell index starting from p=0. With a number of DPsmapped together in one frame, each of the Type 1 DPs are grouped intime, similar to TDM multiplexing of DPs.

Type 2 DPs are first mapped in the increasing order of symbol index, andthen after reaching the last OFDM symbol of the frame, the cell indexincreases by one and the symbol index rolls back to the first availablesymbol and then increases from that symbol index. After mapping a numberof DPs together in one frame, each of the Type 2 DPs are grouped infrequency together, similar to FDM multiplexing of DPs.

Type 1 DPs and Type 2 DPs can coexist in a frame if needed with onerestriction; Type 1 DPs always precede Type 2 DPs. The total number ofOFDM cells carrying Type 1 and Type 2 DPs cannot exceed the total numberof OFDM cells available for transmission of DPs:

D _(DP1) +D _(DP2) ≧D _(DP)  [Expression 2]

where DDP1 is the number of OFDM cells occupied by Type 1 DPs, DDP2 isthe number of cells occupied by Type 2 DPs. Since PLS, EAC, FIC are allmapped in the same way as Type 1 DP, they all follow “Type 1 mappingrule”. Hence, overall, Type 1 mapping always precedes Type 2 mapping.

FIG. 21 illustrates DP mapping according to an embodiment of the presentinvention.

shows an addressing of OFDM cells for mapping type 1 DPs and (b) showsan an addressing of OFDM cells for mapping for type 2 DPs.

Addressing of OFDM cells for mapping Type 1 DPs (0, . . . , DDP1−1) isdefined for the active data cells of Type 1 DPs. The addressing schemedefines the order in which the cells from the TIs for each of the Type 1DPs are allocated to the active data cells. It is also used to signalthe locations of the DPs in the dynamic part of the PLS2.

Without EAC and FIC, address 0 refers to the cell immediately followingthe last cell carrying PLS in the last FSS. If EAC is transmitted andFIC is not in the corresponding frame, address 0 refers to the cellimmediately following the last cell carrying EAC. If FIC is transmittedin the corresponding frame, address 0 refers to the cell immediatelyfollowing the last cell carrying FIC. Address 0 for Type 1 DPs can becalculated considering two different cases as shown in (a). In theexample in (a), PLS, EAC and FIC are assumed to be all transmitted.Extension to the cases where either or both of EAC and FIC are omittedis straightforward. If there are remaining cells in the FSS aftermapping all the cells up to FIC as shown on the left side of (a).

Addressing of OFDM cells for mapping Type 2 DPs (0, . . . , DDP2-1) isdefined for the active data cells of Type 2 DPs. The addressing schemedefines the order in which the cells from the TIs for each of the Type 2DPs are allocated to the active data cells. It is also used to signalthe locations of the DPs in the dynamic part of the PLS2.

Three slightly different cases are possible as shown in (b). For thefirst case shown on the left side of (b), cells in the last FSS areavailable for Type 2 DP mapping. For the second case shown in themiddle, FIC occupies cells of a normal symbol, but the number of FICcells on that symbol is not larger than CFSS. The third case, shown onthe right side in (b), is the same as the second case except that thenumber of FIC cells mapped on that symbol exceeds CFSS.

The extension to the case where Type 1 DP(s) precede Type 2 DP(s) isstraightforward since PLS, EAC and FIC follow the same “Type 1 mappingrule” as the Type 1 DP(s).

A data pipe unit (DPU) is a basic unit for allocating data cells to a DPin a frame.

A DPU is defined as a signaling unit for locating DPs in a frame. A CellMapper 7010 may map the cells produced by the TIs for each of the DPs. ATime interleaver 5050 outputs a series of TI-blocks and each TI-blockcomprises a variable number of XFECBLOCKs which is in turn composed of aset of cells. The number of cells in an XFECBLOCK, Ncells, is dependenton the FECBLOCK size, Nldpc, and the number of transmitted bits perconstellation symbol. A DPU is defined as the greatest common divisor ofall possible values of the number of cells in a XFECBLOCK, Ncells,supported in a given PHY profile. The length of a DPU in cells isdefined as LDPU. Since each PHY profile supports different combinationsof FECBLOCK size and a different number of bits per constellationsymbol, LDPU is defined on a PHY profile basis.

FIG. 22 illustrates an FEC structure according to an embodiment of thepresent invention.

FIG. 22 illustrates an FEC structure according to an embodiment of thepresent invention before bit interleaving. As above mentioned, Data FECencoder may perform the FEC encoding on the input BBF to generateFECBLOCK procedure using outer coding (BCH), and inner coding (LDPC).The illustrated FEC structure corresponds to the FECBLOCK. Also, theFECBLOCK and the FEC structure have same value corresponding to a lengthof LDPC codeword.

The BCH encoding is applied to each BBF (Kbch bits), and then LDPCencoding is applied to BCH-encoded BBF (Kldpc bits=Nbch bits) asillustrated in FIG. 22.

The value of Nldpc is either 64800 bits (long FECBLOCK) or 16200 bits(short FECBLOCK).

The below table 28 and table 29 show FEC encoding parameters for a longFECBLOCK and a short FECBLOCK, respectively.

TABLE 28 BCH error LDPC correction N_(bch) − Rate N_(ldpc) K_(ldpc)K_(bch) capability K_(bch) 5/15 64800 21600 21408 12 192 6/15 2592025728 7/15 30240 30048 8/15 34560 34368 9/15 38880 38688 10/15  4320043008 11/15  47520 47328 12/15  51840 51648 13/15  56160 55968

TABLE 29 BCH error LDPC correction N_(bch) − Rate N_(ldpc) K_(ldpc)K_(bch) capability K_(bch) 5/15 16200 5400 5232 12 168 6/15 6480 63127/15 7560 7392 8/15 8640 8472 9/15 9720 9552 10/15  10800 10632 11/15 11880 11712 12/15  12960 12792 13/15  14040 13872

The details of operations of the BCH encoding and LDPC encoding are asfollows:

A 12-error correcting BCH code is used for outer encoding of the BBF.The BCH generator polynomial for short FECBLOCK and long FECBLOCK areobtained by multiplying together all polynomials.

LDPC code is used to encode the output of the outer BCH encoding. Togenerate a completed Bldpc (FECBLOCK), Pldpc (parity bits) is encodedsystematically from each Ildpc (BCH-encoded BBF), and appended to Ildpc.The completed Bldpc (FECBLOCK) are expressed as followexpression.

B _(ldpc) =[I _(ldpc) P _(ldpc) ]=[i ₀ ,i ₁ , . . . ,i _(K) _(ldpc) ₋₁,p ₀ ,p ₁ , . . . ,p _(N) _(ldpc) _(-K) _(ldpc) ₋₁]  [expression3]

The parameters for long FECBLOCK and short FECBLOCK are given in theabove table 28 and 29, respectively.

The detailed procedure to calculate Nldpc−Kldpc parity bits for longFECBLOCK, is as follows:

1) Initialize the parity bits,

p ₀ =p ₁ =p ₂ = . . . =p _(N) _(ldpc) _(-K) _(ldpc) ₋₁=0  [expression4]

2) Accumulate the first information bit −i0, at parity bit addressesspecified in the first row of an addresses of parity check matrix. Thedetails of addresses of parity check matrix will be described later. Forexample, for rate 13/15:

p ₉₈₃ =p ₉₈₃ ⊕i ₀ p ₂₈₁₅ =p ₂₈₁₅ ⊕i ₀

p ₄₈₃₇ =p ₄₈₃₇ ⊕i ₀ p ₄₉₈₉ =p ₄₉₈₉ ⊕i ₀

p ₆₁₃₈ =p ₆₁₃₈ ⊕i ₀ p ₆₄₅₈ =p ₆₄₅₈ ⊕i ₀

p ₆₉₂₁ =p ₆₉₂₁ ⊕i ₀ p ₆₀₇₄ =p ₆₀₇₄ ⊕i ₀

p ₇₅₇₂ =p ₇₅₇₂ ⊕i ₀ p ₈₂₆₀ =p ₈₂₆₀ ⊕i ₀

p ₈₄₉₆ =p ₈₄₉₆ ⊕i ₀  [expression 5]

3) For the next 359 information bits, is, s=1, 2, . . . , 359 accumulateis at parity bit addresses using following expression.

{x+(s mod 360)×Q _(ldpc)} mod(N _(ldpc) −K _(ldpc))  [expression 6]

where x denotes the address of the parity bit accumulator correspondingto the first bit i0, and Qldpc is a code rate dependent constantspecified in the addresses of parity check matrix. Continuing with theexample, Qldpc=24 for rate 13/15, so for information bit i1, thefollowing operations are performed:

p ₁₀₀₇ =p ₁₀₀₇ ⊕i ₁ p ₂₈₃₉ =p ₂₈₃₉ ⊕i ₁

p ₄₈₆₁ =p ₄₈₆₁ ⊕i ₁ p ₅₀₁₃ =p ₅₀₁₃ ⊕i ₁

p ₆₁₆₂ =p ₆₁₆₂ ⊕i ₁ p ₆₄₈₂ =p ₆₄₈₂ ⊕i ₁

p ₆₉₄₅ =p ₆₉₄₅ ⊕i ₁ p ₆₉₉₈ =p ₆₉₉₈ ⊕i ₁

p ₇₅₉₆ =p ₇₅₉₆ ⊕i ₁ p ₈₂₈₄ =p ₈₂₈₄ ⊕i ₁

p ₈₅₂₀ =p ₈₅₂₀ ⊕i ₁  [expression 7]

4) For the 361st information bit i360, the addresses of the parity bitaccumulators are given in the second row of the addresses of paritycheck matrix. In a similar manner the addresses of the parity bitaccumulators for the following 359 information bits is, s=361, 362, . .. , 719 are obtained using the expression 6, where x denotes the addressof the parity bit accumulator corresponding to the information bit i360,i.e., the entries in the second row of the addresses of parity checkmatrix.

5) In a similar manner, for every group of 360 new information bits, anew row from addresses of parity check matrixes used to find theaddresses of the parity bit accumulators.

After all of the information bits are exhausted, the final parity bitsare obtained as follows:

6) Sequentially perform the following operations starting with i=1

p _(i) =p _(i) ⊕p _(i-1) , i=1=1,2, . . . ,N _(ldpc) −K _(ldpc)−1  [Mathfigure 8]

where final content of pi, i=0,1, . . . Nldpc−Kldpc−1 is equal to theparity bit pi.

TABLE 30 Code Rate Q_(ldpc) 5/15 120 6/15 108 7/15 96 8/15 84 9/15 7210/15  60 11/15  48 12/15  36 13/15  24

This LDPC encoding procedure for a short FECBLOCK is in accordance witht LDPC encoding procedure for the long FECBLOCK, except replacing thetable 30 with table 31, and replacing the addresses of parity checkmatrix for the long FECBLOCK with the addresses of parity check matrixfor the short FECBLOCK.

TABLE 31 Code Rate Q_(ldpc) 5/15 30 6/15 27 7/15 24 8/15 21 9/15 1810/15  15 11/15  12 12/15  9 13/15  6

FIG. 23 illustrates a bit interleaving according to an embodiment of thepresent invention.

The outputs of the LDPC encoder are bit-interleaved, which consists ofparity interleaving followed by Quasi-Cyclic Block (QCB) interleavingand inner-group interleaving.

shows Quasi-Cyclic Block (QCB) interleaving and (b) shows inner-groupinterleaving.

The FECBLOCK may be parity interleaved. At the output of the parityinterleaving, the LDPC codeword consists of 180 adjacent QC blocks in along FECBLOCK and 45 adjacent QC blocks in a short FECBLOCK. Each QCblock in either a long or short FECBLOCK consists of 360 bits. Theparity interleaved LDPC codeword is interleaved by QCB interleaving. Theunit of QCB interleaving is a QC block. The QC blocks at the output ofparity interleaving are permutated by QCB interleaving as illustrated inFIG. 23, where Ncells=64800/η od or 16200/η mod according to theFECBLOCK length. The QCB interleaving pattern is unique to eachcombination of modulation type and LDPC code rate.

After QCB interleaving, inner-group interleaving is performed accordingto modulation type and order (η mod) which is defined in the below table32. The number of QC blocks for one inner-group, NQCB_IG, is alsodefined.

TABLE 32 Modulation type η_(mod) N_(QCB) _(—) _(IG) QAM-16 4 2 NUC-16 44 NUQ-64 6 3 NUC-64 6 6 NUQ-256 8 4 NUC-256 8 8 NUQ-1024 10 5 NUC-102410 10

The inner-group interleaving process is performed with NQCB_IG QC blocksof the QCB interleaving output. Inner-group interleaving has a processof writing and reading the bits of the inner-group using 360 columns andNQCB_IG rows. In the write operation, the bits from the QCB interleavingoutput are written row-wise. The read operation is performed column-wiseto read out m bits from each row, where m is equal to 1 for NUC and 2for NUQ.

FIG. 24 illustrates a cell-word demultiplexing according to anembodiment of the present invention.

FIG. 24 shows a cell-word demultiplexing for 8 and 12 bpcu MIMO and (b)shows a cell-word demultiplexing for 10 bpcu MIMO.

Each cell word (c0,1, c1,1, . . . , cη mod−1,1) of the bit interleavingoutput is demultiplexed into (d1,0,m, d1,1,m . . . , d1,η mod−1,m) and(d2,0,m, d2,1,m . . . , d2,η mod−1,m) as shown in (a), which describesthe cell-word demultiplexing process for one XFECBLOCK.

For the 10 bpcu MIMO case using different types of NUQ for MIMOencoding, the Bit Interleaver for NUQ-1024 is re-used. Each cell word(c0,1, c1,1, c9,1) of the Bit Interleaver output is demultiplexed into(d1,0,m, d1,1,m . . . , d1,3,m) and (d2,0,m, d2,1,m . . . , d2,5,m), asshown in (b).

FIG. 25 illustrates a time interleaving according to an embodiment ofthe present invention.

to (c) show examples of TI mode.

The time interleaver operates at the DP level. The parameters of timeinterleaving (TI) may be set differently for each DP.

The following parameters, which appear in part of the PLS2-STAT data,configure the TI:

DP_TI_TYPE (allowed values: 0 or 1): Represents the TI mode; ‘0’indicates the mode with multiple TI blocks (more than one TI block) perTI group. In this case, one TI group is directly mapped to one frame (nointer-frame interleaving). ‘1’ indicates the mode with only one TI blockper TI group. In this case, the TI block may be spread over more thanone frame (inter-frame interleaving).

DP_TI_LENGTH: If DP_TI_TYPE=‘0’, this parameter is the number of TIblocks NTI per TI group. For DP_TI_TYPE=‘1’, this parameter is thenumber of frames PI spread from one TI group.

DP_NUM_BLOCK_MAX (allowed values: 0 to 1023): Represents the maximumnumber of XFECBLOCKs per TI group.

DP_FRAME_INTERVAL (allowed values: 1, 2, 4, 8): Represents the number ofthe frames HUMP between two successive frames carrying the same DP of agiven PHY profile.

DP_TI_BYPASS (allowed values: 0 or 1): If time interleaving is not usedfor a DP, this parameter is set to ‘1’. It is set to ‘0’ if timeinterleaving is used.

Additionally, the parameter DP_NUM_BLOCK from the PLS2-DYN data is usedto represent the number of XFECBLOCKs carried by one TI group of the DP.

When time interleaving is not used for a DP, the following TI group,time interleaving operation, and TI mode are not considered. However,the Delay Compensation block for the dynamic configuration informationfrom the scheduler will still be required. In each DP, the XFECBLOCKsreceived from the SSD/MIMO encoding are grouped into TI groups. That is,each TI group is a set of an integer number of XFECBLOCKs and willcontain a dynamically variable number of XFECBLOCKs. The number ofXFECBLOCKs in the TI group of index n is denoted by NxBLOCK_Group(n) andis signaled as DP_NUM_BLOCK in the PLS2-DYN data. Note thatNxBLOCK_Group(n) may vary from the minimum value of 0 to the maximumvalue NxBLOCK_Group_MAX (corresponding to DP_NUM_BLOCK_MAX) of which thelargest value is 1023.

Each TI group is either mapped directly onto one frame or spread over PIframes. Each TI group is also divided into more than one TI blocks(NTI), where each TI block corresponds to one usage of time interleavermemory. The TI blocks within the TI group may contain slightly differentnumbers of XFECBLOCKs. If the TI group is divided into multiple TIblocks, it is directly mapped to only one frame. There are three optionsfor time interleaving (except the extra option of skipping the timeinterleaving) as shown in the below table 33.

TABLE 33 Modes Descriptions Option-1 Each TI group contains one TI blockand is mapped directly to one frame as shown in (a). This option issignaled in the PLS2-STAT by DP_TI_TYPE = ‘0’ and DP_TI_LENGTH = ‘1’(N_(TI) = 1). Option-2 Each TI group contains one TI block and is mappedto more than one frame. (b) shows an example, where one TI group ismapped to two frames, i.e., DP_TI_LENGTH = ‘2’ (P_(I) = 2) andDP_FRAME_INTERVAL (I_(JUMP) = 2). This provides greater time diversityfor low data- rate services. This option is signaled in the PLS2- STATby DP_TI_TYPE = ‘1’. Option-3 Each TI group is divided into multiple TIblocks and is mapped directly to one frame as shown in (c). Each TIblock may use full TI memory, so as to provide the maximum bit-rate fora DP. This option is signaled in the PLS2-STAT signaling by DP_TI_TYPE =‘0’ and DP_TI_LENGTH = N_(TI), while P_(I) = 1.

In each DP, the TI memory stores the input XFECBLOCKs (output XFECBLOCKsfrom the SSD/MIMO encoding block). Assume that input XFECBLOCKs aredefined as

(d _(n,s,0,0) , d _(n,s,0,1) , . . . d _(n,s,O,N) _(cells) ⁻¹ , d_(n,s,1,0) , . . . , d _(n,s,1,N) _(cells) ⁻¹ , . . . d _(n,s,N)_(xBLOCK_TI) _((n,s)−1,0) , . . . ,d _(n,s,N) _(xBLOCK_TI) _((n,s)−1,N)_(cells) ⁻¹),

where d_(n,s,r,q) is the qth cell of the rth XFECBLOCK in the sth TIblock of the nth TI group and represents the outputs of SSD and MIMOencodings as follows

$d_{n,s,r,q} = \left\{ {\begin{matrix}{f_{n,s,r,q},} & {{the}\mspace{14mu} {output}\mspace{14mu} {of}\mspace{14mu} S\; S\; D\mspace{14mu} \ldots \mspace{14mu} {encoding}} \\{g_{n,s,r,q},} & {{the}\mspace{14mu} {output}\mspace{14mu} {of}\mspace{14mu} {MIMO}\mspace{14mu} {encoding}}\end{matrix}.} \right.$

In addition, assume that output XFECBLOCKs from the time interleaver5050 are defined as

(h _(n,s,0) , h _(n,s,1) , . . . h _(n,s,i) , . . . h _(n,s,N)_(xBLOCK_TI) _((n,s)×N) _(cells) ⁻¹)

where h_(n,s,i) is the ith output cell (for i=0, . . . , N_(xBLOCK) _(_)_(TI)(n,s)×N_(cells)−1) in the sth TI block of the nth TI group.

Typically, the time interleaver will also act as a buffer for DP dataprior to the process of frame building. This is achieved by means of twomemory banks for each DP. The first TI-block is written to the firstbank. The second TI-block is written to the second bank while the firstbank is being read from and so on.

The TI is a twisted row-column block interleaver. For the sth TI blockof the nth TI group, the number of rows N_(r) of a TI memory is equal tothe number of cells N_(cells), i.e., N_(r)=N_(cells) while the number ofcolumns N_(c) is equal to the number N_(xBLOCK) _(_) _(TI)(n,s).

FIG. 26 illustrates the basic operation of a twisted row-column blockinterleaver according to an embodiment of the present invention.

FIG. 26 (a) shows a writing operation in the time interleaver and FIG.26(b) shows a reading operation in the time interleaver The firstXFECBLOCK is written column-wise into the first column of the TI memory,and the second XFECBLOCK is written into the next column, and so on asshown in (a). Then, in the interleaving array, cells are read outdiagonal-wise. During diagonal-wise reading from the first row(rightwards along the row beginning with the left-most column) to thelast row, N_(r) cells are read out as shown in (b). In detail, assumingz_(n,s,i)(i=0, . . . , N_(r)N_(c)) as the TI memory cell position to beread sequentially, the reading process in such an interleaving array isperformed by calculating the row index R_(n,s,i), the column indexC_(n,s,i) and the associated twisting parameter T_(n,s,i) as followsexpression.

$\begin{matrix}{{{GENERATE}\left( {R_{n,s,i},C_{n,s,i}} \right)} = \left\{ {{R_{n,s,i} = {{mod}\; \left( {i,N_{r}} \right)}},{T_{n,s,i} = {{mod}\; \left( {{S_{shift} \times R_{n,s,i}},N_{c}} \right)}},{C_{n,s,i} = {{mod}\; \left( {{T_{n,s,i} + \left\lfloor \frac{i}{N_{r}} \right\rfloor},N_{c}} \right)}}} \right\}} & \left\lbrack {{expression}\mspace{14mu} 9} \right\rbrack\end{matrix}$

where S_(shift) is a common shift value for the diagonal-wise readingprocess regardless of N_(xBLOCK) _(_) _(TI)(n,s), and it is determinedby N_(xBLOCK) _(_) _(TI) _(_) _(max) given in the PLS2-STAT as followsexpression.

                                    [expression  10]$\mspace{79mu} {{for}\mspace{14mu} \left\{ {\begin{matrix}{{N_{{xBLOCK\_ TI}{\_ MAX}}^{\prime} = {N_{{xBLOCK\_ TI}{\_ MAX}} + 1}},} & {{{if}\mspace{14mu} N_{{xBLOCK\_ TI}{\_ MAX}}{mod}\; 2} = 0} \\{{N_{{xBLOCK\_ TI}{\_ MAX}}^{\prime} = N_{{xBLOCK\_ TI}{\_ MAX}}},} & {{{if}\mspace{14mu} N_{{xBLOCK\_ TI}{\_ MAX}}{mod}\; 2} = 1}\end{matrix},\mspace{20mu} {S_{shift} = \frac{N_{{xBLOCK\_ TI}{\_ MAX}}^{\prime} - 1}{2}}} \right.}$

As a result, the cell positions to be read are calculated by acoordinate as z_(n,s,i)=N_(r)C_(n,s,i)+R_(n,s,i).

FIG. 27 illustrates an operation of a twisted row-column blockinterleaver according to another embodiment of the present invention.

More specifically, FIG. 27 illustrates the interleaving array in the TImemory for each TI group, including virtual XFECBLOCKs when N_(xBLOCK)_(_) _(TI)(0,0)=3, N_(xBLOCK) _(_) _(TI)(1,0)=6, N_(xBLOCK) _(_)_(TI)(2,0)=5.

The variable number N_(xBLOCK) _(_) _(TI)(n,s)=N_(r) will be less thanor equal to N_(xBLOCK) _(_) _(TI) _(_) _(MAX)′. Thus, in order toachieve a single-memory deinterleaving at the receiver side, regardlessof N_(xBLOCK) _(_) _(TI)(n,s), the interleaving array for use in atwisted row-column block interleaver is set to the size ofN_(r)×N_(c)=N_(cells)×N_(xBLOCK) _(_) _(TI) _(_) _(MAX)′ by insertingthe virtual XFECBLOCKs into the TI memory and the reading process isaccomplished as follow expression.

  expression11 p = 0; for i = 0;i < N _(cells)N′_(xBLOCK)__(TI)__(MAX);i = i + 1 {GENERATE (R_(n,s,i),C_(n,s,i)); V_(i) = N_(r)C_(n,s,j) +R_(n,s,j)  if V_(i) < N_(cells)N_(xBLOCK)_TI (n,s)  {   Z_(n,s,p) =V_(i); p = p + 1;   } }

The number of TI groups is set to 3. The option of time interleaver issignaled in the PLS2-STAT data by DP_TI_TYPE=‘0’, DP_FRAME_INTERVAL=‘1’,and DP_TI_LENGTH=‘1’, i.e., NTI=1, IJUMP=1, and PI=1. The number ofXFECBLOCKs, each of which has Ncells=30 cells, per TI group is signaledin the PLS2-DYN data by NxBLOCK_TI(0,0)=3, NxBLOCK_TI(1,0)=6, andNxBLOCK_TI(2,0)=5, respectively. The maximum number of XFECBLOCK issignaled in the PLS2-STAT data by NxBLOCK_Group_MAX, which leads to└N_(xBLOCK) _(_) _(Group) _(_) _(MAX)/N^(TI)┘=N_(xBLOCK) _(_) _(TI) _(_)_(MAX)=6.

FIG. 28 illustrates a diagonal-wise reading pattern of a twistedrow-column block interleaver according to an embodiment of the presentinvention.

More specifically FIG. 28 shows a diagonal-wise reading pattern fromeach interleaving array with parameters of N_(xBLOCK) _(_) _(TI) _(_)_(MAX)′=7 and Sshift=(7−1)/2=3. Note that in the reading process shownas pseudocode above, if V_(i)≧N_(cells)N_(xBLOCK) _(_) _(TI)(n,s) thevalue of Vi is skipped and the next calculated value of Vi is used.

FIG. 29 illustrates interlaved XFECBLOCKs from each interleaving arrayaccording to an embodiment of the present invention.

FIG. 29 illustrates the interleaved XFECBLOCKs from each interleavingarray with parameters of N_(xBLOCK) _(_) _(TI) _(_) _(MAX)′=7 andSshift=3.

A description is now given of a frequency interleaving process accordingto an embodiment of the present invention.

The frequency interleaver 7020 according to an embodiment of the presentinvention is used to apply a different interleaving sequence per cellscorresponding to an every OFDM symbol to improve the performance offrequency diversity in an OFDM symbol structure including a plurality ofcells.

In the present invention, the above-described frequency interleavingmethod may be called random frequency interleaving or random FI, and thename thereof may vary depending on the intention of a designer.

As described above, the broadcast signal transmission apparatus or thefrequency interleaver 7020 included in the broadcast signal transmissionapparatus according to an embodiment of the present invention performsfrequency interleaving by applying a different interleaving sequence percells of one or more OFDM symbols, i.e., each OFDM symbol or paired twoOFDM symbols (pair-wise OFDM symbols or each OFDM symbol pair), and thusmay achieve frequency diversity. The frequency interleaver according toan embodiment of the present invention may perform frequencyinterleaving on input OFDM symbols using frequency interleavingaddresses generated based on a main interleaving sequence (or a basicinterleaving sequence) and a symbol offset. A detailed descriptionthereof will be given below.

Therefore, the broadcast signal transmission apparatus or the frequencyinterleaver according to an embodiment of the present invention may havea ping-pong frequency interleaver structure for performing frequencyinterleaving in units of a pair of consecutive OFDM symbols using twomemory banks. The name thereof may vary depending on the intention of adesigner.

Data cells corresponding to even pair-wise OFDM symbols and data cellscorresponding to odd pair-wise OFDM symbols may be independentlyinterleaved using different FI memory banks. In addition, the frequencyinterleaver according to an embodiment of the present invention maysimultaneously perform write operation and read operation on data cellscorresponding to a pair of consecutive OFDM symbols input to each memorybank, using a single arbitrary interleaving sequence. A detaileddescription thereof will be given below.

FIG. 30 illustrates operation of the frequency interleaver according toan embodiment of the present invention.

Specifically, FIG. 30 illustrates basic operation of the frequencyinterleaver using two memory banks at the transmitter side. Frequencyinterleaving according to an embodiment of the present invention mayenable frequency deinterleaving using a single memory at the receiverside.

As described above, the frequency interleaver according to an embodimentof the present invention may perform ping-pong interleaving operation.

In general, the ping-pong interleaving operation is performed using twomemory banks.

As described above, data cells corresponding to even pair-wise OFDMsymbols and data cells corresponding to odd pair-wise OFDM symbols maybe independently interleaved using different FI memory banks. Forexample, data cells corresponding to the first (even pair-wise) OFDMsymbols may be frequency-interleaved in the first memory bank based onan interleaving sequence according to an embodiment of the presentinvention, and data cells corresponding to the second (odd pair-wise)OFDM symbols may be frequency-interleaved in the second memory bankbased on an interleaving sequence according to an embodiment of thepresent invention.

As illustrated in the figure, the frequency interleaver may include ademux tO, memory bank A 16100, memory bank B 16200, and a mux 16300.

Initially, the frequency interleaver according to an embodiment of thepresent invention may perform demultiplexing to pair data cellscorresponding to consecutively input OFDM symbols. Subsequently, thefrequency interleaver according to an embodiment of the presentinvention may perform frequency interleaving including write operationand read operation using each memory bank A or B.

Then, the frequency interleaver according to an embodiment of thepresent invention may perform multiplexing to consecutively transmit thedata cells corresponding to the OFDM symbols.

FIG. 31 illustrates a frequency deinterleaving process according to anembodiment of the present invention.

The broadcast signal reception apparatus according to an embodiment ofthe present invention may perform an inverse process of theabove-described frequency interleaving process using a single memory.This figure illustrates a frequency deinterleaving process of data cellscorresponding to consecutively input OFDM symbols using a single memory.

Frequency deinterleaving according to an embodiment of the presentinvention may be basically performed as an inverse process of theabove-described frequency interleaving process.

That is, as illustrated in a left part of the figure, the broadcastsignal reception apparatus according to an embodiment of the presentinvention may perform inverse operations of the write operation and theread operation of the above-described frequency interleaving process ofthe data cells corresponding to the consecutively input OFDM symbolsusing a single memory. In this case, since only a single memory is used,memory use efficiency may be increased. This effect is generated due tothe ping-pong interleaving operation performed at the transmitter side.

FIG. 32 is a view illustrating single-memory deinterleaving for inputsequential OFDM symbols.

FIG. 32 is a view illustrating concept of a broadcast signal receivingapparatus or a frequency deinterleaver thereof, for applyinginterleaving sequence used in a broadcast signal transmitting apparatus(or a frequency interleaver 7020) to each pair-wise OFDM symbol toperform deinterleaving.

As described above, the broadcast signal receiving apparatus accordingto an embodiment of the present invention may perform an inverseprocedure of the aforementioned frequency interleaving procedure using asingle memory. FIG. 32 illustrates an operation of the broadcast signalreceiving apparatus for processing single-memory frequencydeinterleaving (FDI) for input sequential OFDM symbols.

The broadcast signal receiving apparatus according to an embodiment ofthe present invention may perform an inverse procedure of theaforementioned operation of a frequency interleaver 7020. Thus,deinterleaving sequences correspond to the aforementioned interleavingsequences.

FIG. 33 illustrates equations for describing a process for changing aninterleaving sequence within each memory bank, according to anembodiment of the present invention.

As described above, the frequency interleaver according to an embodimentof the present invention may perform frequency interleaving usingfrequency interleaving addresses calculated by generating a symboloffset based on a basic interleaving sequence.

A block of an upper part of the figure illustrates an equation showing afrequency interleaving process of data cells corresponding to the firstOFDM symbol of an i^(th) OFDM symbol pair, and a block of a lower partof the figure illustrates an equation showing a frequency interleavingprocess of data cells corresponding to the second OFDM symbol of theOFDM symbol pair.

A random sequence may be generated by a basic interleaving sequencegenerator. A detailed description thereof will be given below.

The symbol offset may be generated by a symbol offset generator to bedescribed below. A detailed description thereof will be given below.

Available data cells (cells output from the cell mapper 7010) may beinterleaved within one OFDM symbol. According to an embodiment of thepresent invention, N_(data) denotes the number of data cells, and themaximum value of N_(data) may be denoted by N_(max) or M_(max). Thevalue of N_(max) may vary depending on FFT mode, and the name or valuethereof may vary depending on the intention of a designer.

Hj(k) denotes an interleaving address or interleaving sequence for eachFFT mode. As described above, the frequency interleaver 7020 accordingto an embodiment of the present invention randomly interleaves datacells corresponding to one OFDM symbol and uses the same to achievefrequency diversity. Therefore, to achieve the maximum interleaving gainin one signal frame, the frequency interleaver 7020 according to anembodiment of the present invention may apply an interleaving sequencein units of data cells corresponding to an OFDM symbol pair includingtwo consecutive OFDM symbols.

In addition, as described above, the OFDM generation block 1030according to an embodiment of the present invention may perform IFFT oninput data.

A description is now given of operation of the frequency interleaver7020 for generating a random interleaving sequence.

A random interleaving sequence generator may refer to the frequencyinterleaver itself, or may be understood as a block or a module includedin the frequency interleaver.

The random interleaving sequence generator may be called an interleavingaddress generator or an interleaving sequence generator, and the namethereof may vary depending on the intention of a designer. Theinterleaving sequence generator according to an embodiment of thepresent invention may include a basic interleaving sequence generator, asymbol offset generator, a modulo operator, and an address check block.The basic interleaving sequence generator according to an embodiment ofthe present invention may be called a random main sequence generator,and the address check block may be called a memory index check block.The name, location, and function of each block may vary depending on theintention of a designer.

As described above, the FFT mode or FFT size according to an embodimentof the present invention may be, for example, 8K, 16K, or 32K. The FFTmode or size may vary depending on the intention of a designer.

A description is now given of the random interleaving sequencegenerator.

The frequency interleaver according to an embodiment of the presentinvention may perform interleaving by applying a different interleavingsequence or interleaving address per OFDM symbol as described above,thereby achieving frequency diversity. The logical composition of therandom interleaving sequence generator according to an embodiment of thepresent invention may include a random main sequence generator C_(j)(K)for interleaving data cells included in every single OFDM symbol, and arandom symbol offset generator S_(└j/2┘) or generating and changing asymbol offset. In addition, the random interleaving sequence generatoraccording to an embodiment of the present invention may generate theabove-described interleaving sequence or interleaving address.

As described above, the random main sequence generator according to anembodiment of the present invention may be called a basic interleavingsequence generator, and the name thereof may vary depending on theintention of a designer. The random main sequence generator according toan embodiment of the present invention uses a binary sequence of aspecific size determined per FFT mode, and may generate a main sequence.

The random main sequence generator according to an embodiment of thepresent invention may include a spreader and a randomizer, and mayperform rendering for full randomness in the frequency domain.

The random symbol offset generator according to an embodiment of thepresent invention may be called the above-described symbol offsetgenerator, and the name thereof may vary depending on the intention of adesigner.

The symbol offset generator according to an embodiment of the presentinvention may include a k-bit spreader and an (X-k)-bit randomizer, andmay perform rendering for spreading by 2k in the time domain.

The above-described spreader and the randomizer may be used to generatea spreading effect and a randomization effect when an interleavingsequence is generated.

A description is now given of the frequency interleaver in a case whenthe FFT size is 8K.

The frequency interleaver according to an embodiment of the presentinvention may include the following logical structure in 8K FFT mode.

The basic interleaving sequence generator may include a 1-bit spreaderand a 12-bit randomizer, and the symbol offset generator may include ak-bit spreader and a (13-k)-bit randomizer. The sizes of the spreaderand the randomizer may vary depending on the intention of a designer.

FIG. 34 illustrates a symbol offset generator of 8K FFT mode andequations showing operation of the symbol offset generator, according toan embodiment of the present invention.

In this figure, (a) illustrates a symbol offset generator including a0-bit spreader and a 13-bit randomizer, and (b) illustrates equationsshowing operation of the symbol offset generator of 8K FFT mode.

The symbol offset generator illustrated in (a) may operate in units ofan OFDM symbol pair.

The equation illustrated in an upper part of (b) shows an initial valueand a primitive polynomial (PP) of the randomizer. In this case, the PPmay be a 13^(th) PP and the initial value may be changed to arbitraryvalues.

The equation illustrated in a lower part of (b) shows a process forcalculating and outputting a symbol offset for output signals of thespreader and the randomizer. As shown in the equation, the symbol offsetgenerator may operate in units of an OFDM symbol pair, and a totallength of output offsets corresponds to half of a total length of OFDMsymbols.

FIG. 35 illustrates a symbol offset generator of 8K FFT mode andequations showing operation of the symbol offset generator, according toanother embodiment of the present invention.

In this figure, (a) illustrates a symbol offset generator including a2-bit spreader and an 11-bit randomizer, and (b) illustrates equationsshowing operation of the symbol offset generator of 8K FFT mode.

The symbol offset generator illustrated in (a) may operate for datacells corresponding to every OFDM symbol pair.

The equation illustrated in an upper part of (b) shows an initial valueand a PP of the randomizer. In this case, the PP may be an 11^(th) PPand the initial value may be changed to arbitrary values.

The equation illustrated in a lower part of (b) shows a process forcalculating and outputting a symbol offset for output signals of thespreader and the randomizer. As shown in the equation, the symbol offsetgenerator may operate for data cells corresponding to every OFDM symbolpair. Therefore, a total length of output offsets corresponds to half ofa total length of OFDM symbols.

FIG. 36 illustrates a frequency interleaver of 8K FFT mode according toan embodiment of the present invention.

The frequency interleaver of 8K FFT mode according to an embodiment ofthe present invention may include a spreader (or a 1-bit toggle switch),a randomizer, a random symbol offset generator (or a symbol offsetgenerator), a modulo operator, and a memory index check block togenerate the above-described interleaving sequence or interleavingaddress. The spreader and the randomizer may be included in theabove-described basic interleaving sequence generator, and the memoryindex check block may be called an address check block. The locations ofthe spreader and the randomizer and the name of the memory index checkblock may vary depending on the intention of a designer.

As illustrated in the figure, the frequency interleaver according to anembodiment of the present invention may perform modulo operation andverify a memory index of the generated interleaving sequence (or verifyan address of the generated interleaving sequence). This serves toincrease the performance of frequency deinterleaving to be performedusing a single memory at the receiver side. As described above,according to an embodiment of the present invention, a signal frame (ora frame) may include normal data symbols (or data symbols), frame edgesymbols, and frame signaling symbols. In this case, since the lengths ofthe frame edge symbols and the frame signaling symbols are less than thelength of the normal data symbols, the deinterleaving performance of afrequency deinterleaver having a single memory may be lowered.Therefore, the present invention proposes frequency interleaving forchecking an address (or a memory index) of an interleaving sequenceafter modulo operation to increase the performance of frequencydeinterleaving.

A description is now given of operation of each block.

The spreader may operate using upper n bits among a total of 13 bits,and may serve as a multiplexer based on a look-up table. In 8K FFT mode,the spreader may be a 1-bit multiplexer (or toggle switch).

The randomizer operates using a PN (or pseudo random bit stream (PRBS))generator and may provide a full randomness effect in interleaving. Asdescribed above, in 8K FFT mode, a PN (or PRBS) generator considering 12bits may be used. The size of the PN (or PRBS) generator may varydepending on the intention of a designer.

The symbol offset generator may generate a symbol offset to be appliedto data cells corresponding to every OFDM symbol pair. As illustrated inthe figure, in the case of 8K, the symbol offset may be determined basedon a bit sequence of 13 bits. As a result, the generated symbol offsetmay have a constant value for two consecutive symbols included in anOFDM symbol pair. A detailed description thereof has been given aboveand thus is omitted herein.

The modulo operator may operate if an input value exceeds N_(data) orN_(max). In 8K FFT mode, the maximum value of N_(max) may be 8192.

If a currently generated value exceeds N_(data) or the maximum valueN_(max) of N_(data), the memory index check block does not use an outputvalue of the modulo operator, and may repeatedly operate the spreaderand the randomizer to control the output memory index (or interleavingaddress) value not to exceed N_(data) or the maximum value N_(max) ofN_(data).

FIG. 37 illustrates equations showing operation of the frequencyinterleaver of 8K FFT mode according to an embodiment of the presentinvention.

The equation illustrated in an upper part of the figure illustrates aninitial value and a PP of the randomizer included in the above-describedbasic interleaving sequence generator. In this case, the PP may be a12^(th) PP and the initial value may be changed to arbitrary values.That is, the equation illustrated in the upper part of the figureillustrates a binary word sequence which can be used to define theabove-described basic interleaving sequence.

The equation illustrated in a lower part of the figure illustrates aprocess for calculating an interleaving sequence (or an interleavingaddress) by the frequency interleaver using an output signal of thebasic interleaving sequence generator. As shown in the equation, agenerated symbol offset may be used to output the interleaving sequence,and modulo operation and address check operation are performed. Asdescribed above, one symbol offset may be equally applied to data cellscorresponding to every OFDM symbol pair.

As described above, the symbol offset generator according to anembodiment of the present invention may include a k-bit spreader and an(X-k)-bit randomizer.

The k-bit spreader operates using a 2^(k) multiplexer, and may beoptimally designed to minimize spreading (or to minimize correlation)between symbols.

The randomizer operates using an N-bit PN generator (or an N-bit PRBSgenerator), and may be designed to provide randomness.

The symbol offset generator of 8K FFT mode may include a 0/1/2-bitspreader and a 13/12/11-bit random number generator (or PN generator).The sizes of the spreader and the random number generator may varydepending on the intention of a designer.

FIG. 38 illustrates the logical structure of the frequency interleaverof 8K FFT mode according to an embodiment of the present invention.

As described above, the frequency interleaver of 8K FFT mode accordingto an embodiment of the present invention may include a basicinterleaving sequence generator, a symbol offset generator, a modulooperator, and a memory index check block.

Detailed descriptions thereof have been given above and thus are omittedherein.

A description is now given of a frequency interleaver of 8K FFT modeaccording to another embodiment of the present invention. The frequencyinterleaver of 8K FFT mode according to another embodiment of thepresent invention is different from the above-described frequencyinterleaver in that a randomizer of a basic interleaving sequencefurther performs bit shuffling.

FIG. 39 illustrates a frequency interleaver of 8K FFT mode according toanother embodiment of the present invention.

The frequency interleaver of 8K FFT mode according to another embodimentof the present invention may include a basic interleaving sequencegenerator, a symbol offset generator, a modulo operator, and a memoryindex check block to generate the above-described interleaving sequenceor interleaving address, and the basic interleaving sequence generatorperforms bit shuffling. Detailed descriptions of operations other thanbit shuffling have been given above and thus are omitted herein.

Bit shuffling is performed to optimize spreading or randomness, and isdesigned in consideration of N_(data). In 8K FFT mode, the randomizermay use a 12-bit PN generator, and the size of the PN generator mayvary.

FIG. 40 illustrates bit shuffling of the frequency interleaver of 8K FFTmode and equations showing operation of the frequency interleaver,according to an embodiment of the present invention.

In this figure, (a) illustrates the above-described bit shuffling of 8KFFT mode, and (b) illustrates equations showing operation of thefrequency interleaver of 8K FFT mode.

As illustrated in (a), bit shuffling of 8K FFT mode may be used toshuffle bits of registers of a PN generator when a memory index iscalculated. An upper part of (a) illustrates operation of bit shuffling,and a lower part of (a) illustrates an example of bit shuffling in thecase of 12 bits.

As illustrated in the figure, as a result of bit shuffling, a 12-bitbinary word sequence used as a basic interleaving sequence of thefrequency interleaver of 8K FFT mode may be changed to R or R′. Thechanged binary word sequence may be equally applied to data cellscorresponding to every OFDM symbol pair, or applied differently per datacells corresponding to each of two OFDM symbols included in an OFDMsymbol pair.

The equation illustrated in an upper part of (b) shows an initial valueand a PP of the randomizer included in the above-described basicinterleaving sequence generator. In this case, the PP may be a 12^(th)PP and the initial value may be changed to arbitrary values. That is,the equation illustrated in the upper part of the figure illustrates abinary word sequence which can be used to define the above-describedbasic interleaving sequence. The equation illustrated in a lower part of(b) shows a process for calculating an interleaving sequence (or aninterleaving address) by the frequency interleaver using an outputsignal of the basic interleaving sequence generator. As shown in theequation, a symbol offset may be used to output the interleavingsequence, and modulo operation and address check operation areperformed. As described above, one symbol offset may be equally appliedto data cells corresponding to every OFDM symbol pair.

A description is now given of the frequency interleaver in a case whenthe FFT size is 16K.

The frequency interleaver according to an embodiment of the presentinvention may include the following logical structure in 16K FFT mode.The basic interleaving sequence generator may include a 1-bit spreaderand a 13-bit randomizer, and the symbol offset generator may include ak-bit spreader and a (14-k)-bit randomizer. The sizes of the spreaderand the randomizer may vary depending on the intention of a designer.

FIG. 41 illustrates a symbol offset generator of 16K FFT mode andequations showing operation of the symbol offset generator, according toan embodiment of the present invention.

In this figure, (a) illustrates a symbol offset generator including a0-bit spreader and a 14-bit randomizer, and (b) illustrates equationsshowing operation of the symbol offset generator of 16K FFT mode.

The symbol offset generator illustrated in (a) may operate in units ofdata cells corresponding to every OFDM symbol pair.

The equation illustrated in an upper part of (b) shows an initial valueand a PP of the randomizer. In this case, the PP may be a 14^(th) PP andthe initial value may be changed to arbitrary values.

The equation illustrated in a lower part of (b) shows a process forcalculating and outputting a symbol offset for output signals of thespreader and the randomizer. As shown in the equation, the symbol offsetgenerator may operate in units of data cells corresponding to every OFDMsymbol pair, and a total length of output offsets corresponds to half ofa total length of OFDM symbols.

FIG. 42 illustrates a symbol offset generator of 16K FFT mode andequations showing operation of the symbol offset generator, according toanother embodiment of the present invention.

In this figure, (a) illustrates a symbol offset generator including a2-bit spreader and a 12-bit randomizer, and (b) illustrates equationsshowing operation of the symbol offset generator of 16K FFT mode.

The symbol offset generator illustrated in (a) may operate in units ofdata cells corresponding to every OFDM symbol pair.

The equation illustrated in an upper part of (b) shows an initial valueand a PP of the randomizer. In this case, the PP may be a 12^(th) PP andthe initial value may be changed to arbitrary values.

The equation illustrated in a lower part of (b) shows a process forcalculating and outputting a symbol offset for output signals of thespreader and the randomizer. As shown in the equation, the symbol offsetgenerator may operate in units of data cells corresponding to every OFDMsymbol pair. Therefore, a total length of output offsets corresponds tohalf of a total length of data symbols corresponding to OFDM symbols.

FIG. 43 illustrates a frequency interleaver of 16K FFT mode according toan embodiment of the present invention.

The frequency interleaver of 16K FFT mode according to an embodiment ofthe present invention may include a spreader (or a 1-bit toggle switch),a randomizer, a random symbol offset generator (or a symbol offsetgenerator), a modulo operator, and a memory index check block togenerate the above-described interleaving sequence or interleavingaddress. The spreader and the randomizer may be included in theabove-described basic interleaving sequence generator, and the memoryindex check block may be called an address check block. The locations ofthe spreader and the randomizer and the name of the memory index checkblock may vary depending on the intention of a designer. A descriptionis now given of operation of each block.

The spreader may operate using upper n bits among a total of 14 bits,and may serve as a multiplexer based on a look-up table. In 16K FFTmode, the spreader may be a 1-bit multiplexer (or toggle switch).

The randomizer operates using a PN (or pseudo random bit stream (PRBS))generator and may provide a full randomness effect in interleaving. Asdescribed above, in 16K FFT mode, a PN (or PRBS) generator considering13 bits may be used. The size of the PN (or PRBS) generator may varydepending on the intention of a designer.

The symbol offset generator may generate a symbol offset to be appliedto data cells corresponding to every OFDM symbol pair. As illustrated inthe figure, in the case of 16K, the symbol offset may be determinedbased on a bit sequence of 14 bits. The value of the symbol offset isconstant for data cells corresponding to two consecutive symbolsincluded in an OFDM symbol pair.

The modulo operator may operate if an input value exceeds N_(data) orN_(max). In 16K FFT mode, the maximum value of N_(max) may be 16384.

If a currently generated value exceeds N_(data) or the maximum valueN_(max) of N_(data), the memory index check block may not use an outputvalue of the modulo operator, and may repeatedly operate the spreaderand the randomizer to control the output memory index value (orinterleaving address) not to exceed N_(data) or the maximum valueN_(max) of N_(data).

FIG. 44 illustrates equations showing operation of the frequencyinterleaver of 16K FFT mode according to an embodiment of the presentinvention.

The equation illustrated in an upper part of the figure illustrates aninitial value and a PP of the randomizer included in the above-describedbasic interleaving sequence generator. In this case, the PP may be a13^(th) PP and the initial value may be changed to arbitrary values.That is, the equation illustrated in the upper part of the figureillustrates a binary word sequence which can be used to define theabove-described basic interleaving sequence.

The equation illustrated in a lower part of the figure illustrates aprocess for calculating an interleaving sequence (or an interleavingaddress) by the frequency interleaver using an output signal of thebasic interleaving sequence generator. As shown in the equation, asymbol offset may be used to output the interleaving sequence, andmodulo operation and address check operation are performed. As describedabove, one symbol offset may be equally applied to data cellscorresponding to every OFDM symbol pair.

As described above, the symbol offset generator according to anembodiment of the present invention may include a k-bit spreader and an(X-k)-bit randomizer.

The k-bit spreader operates using a 2^(k) multiplexer, and may beoptimally designed to minimize spreading (or to minimize correlation)between symbols.

The randomizer operates using an N-bit PN generator (or an N-bit PRBSgenerator), and may be designed to provide randomness.

The symbol offset generator of 16K FFT mode may include a 0/1/2-bitspreader and a 14/13/12-bit random number generator (or PN generator).The sizes of the spreader and the random number generator may varydepending on the intention of a designer.

FIG. 45 illustrates the logical structure of the frequency interleaverof 16K FFT mode according to an embodiment of the present invention.

As described above, the frequency interleaver of 16K FFT mode accordingto an embodiment of the present invention may include a basicinterleaving sequence generator, a symbol offset generator, a modulooperator, and a memory index check block.

Detailed descriptions thereof have been given above and thus are omittedherein.

A description is now given of a frequency interleaver of 16K FFT modeaccording to another embodiment of the present invention. The frequencyinterleaver of 16K FFT mode according to another embodiment of thepresent invention is different from the above-described frequencyinterleaver in that a randomizer of a basic interleaving sequencefurther performs bit shuffling.

FIG. 46 illustrates a frequency interleaver of 16K FFT mode according toanother embodiment of the present invention.

The frequency interleaver of 16K FFT mode according to anotherembodiment of the present invention may include a basic interleavingsequence generator, a symbol offset generator, a modulo operator, and amemory index check block to generate the above-described interleavingsequence or interleaving address, and the basic interleaving sequencegenerator performs bit shuffling. Detailed descriptions of operationsother than bit shuffling have been given above and thus are omittedherein.

Bit shuffling is performed to optimize spreading or randomness, and isdesigned in consideration of N_(data). In 16K FFT mode, the randomizermay use a 13-bit PN generator, and the size of the PN generator mayvary.

FIG. 47 illustrates bit shuffling of the frequency interleaver of 16KFFT mode and equations showing operation of the frequency interleaver,according to an embodiment of the present invention.

In this figure, (a) illustrates the above-described bit shuffling of 16KFFT mode, and (b) illustrates equations showing operation of thefrequency interleaver of 16K FFT mode.

As illustrated in (a), bit shuffling of 16K FFT mode may be used toshuffle bits of registers of a PN generator when a memory index iscalculated. An upper part of (a) illustrates operation of bit shuffling,and a lower part of (a) illustrates an example of bit shuffling in thecase of 13 bits.

As illustrated in the figure, as a result of bit shuffling, a 13-bitbinary word sequence used as a basic interleaving sequence of thefrequency interleaver of 16K FFT mode may be changed to R or R′. Thechanged binary word sequence may be equally applied to data cellscorresponding to every OFDM symbol pair, or applied differently per datacells corresponding to each of two OFDM symbols included in an OFDMsymbol pair.

The equation illustrated in an upper part of (b) shows an initial valueand a PP of the randomizer included in the above-described basicinterleaving sequence generator. In this case, the PP may be a 13^(th)PP and the initial value may be changed to arbitrary values. That is,the equation illustrated in the upper part of the figure illustrates abinary word sequence which can be used to define the above-describedbasic interleaving sequence. The equation illustrated in a lower part of(b) shows a process for calculating an interleaving sequence (or aninterleaving address) by the frequency interleaver using an outputsignal of the basic interleaving sequence generator. As shown in theequation, a symbol offset may be used to output the interleavingsequence, and modulo operation and address check operation areperformed. As described above, one symbol offset may be equally appliedto data cells corresponding to every OFDM symbol pair.

A description is now given of the frequency interleaver in a case whenthe FFT size is 32K.

The frequency interleaver according to an embodiment of the presentinvention may include the following logical structure in 32K FFT mode.

The basic interleaving sequence generator may include a 1-bit spreaderand a 14-bit randomizer, and the symbol offset generator may include ak-bit spreader and a (15-k)-bit randomizer. The sizes of the spreaderand the randomizer may vary depending on the intention of a designer.

FIG. 48 illustrates a symbol offset generator of 32K FFT mode andequations showing operation of the symbol offset generator, according toan embodiment of the present invention.

In this figure, (a) illustrates a symbol offset generator including a0-bit spreader and a 15-bit randomizer, and (b) illustrates equationsshowing operation of the symbol offset generator of 32K FFT mode.

The symbol offset generator illustrated in (a) may operate in units ofdata cells corresponding to every OFDM symbol pair.

The equation illustrated in an upper part of (b) shows an initial valueand a PP of the randomizer. In this case, the PP may be a 15^(th) PP andthe initial value may be changed to arbitrary values.

The equation illustrated in a lower part of (b) shows a process forcalculating and outputting a symbol offset for output signals of thespreader and the randomizer. As shown in the equation, the symbol offsetgenerator may operate in units of data cells corresponding to every OFDMsymbol pair. Therefore, a total length of output offsets corresponds tohalf of a total length of data symbols corresponding to OFDM symbols.

FIG. 49 illustrates a symbol offset generator of 32K FFT mode andequations showing operation of the symbol offset generator, according toanother embodiment of the present invention.

In this figure, (a) illustrates a symbol offset generator including a2-bit spreader and a 13-bit randomizer, and (b) illustrates equationsshowing operation of the symbol offset generator of 32K FFT mode.

The symbol offset generator illustrated in (a) may operate in units ofan OFDM symbol pair.

The equation illustrated in an upper part of (b) shows an initial valueand a PP of the randomizer. In this case, the PP may be a 13^(th) PP andthe initial value may be changed to arbitrary values.

The equation illustrated in a lower part of (b) shows a process forcalculating and outputting a symbol offset for output signals of thespreader and the randomizer. As shown in the equation, the symbol offsetgenerator may operate in units of data cells corresponding to every OFDMsymbol pair. Therefore, a total length of output offsets corresponds tohalf of a total length of data symbols corresponding to OFDM symbols.

FIG. 50 illustrates a frequency interleaver of 32K FFT mode according toan embodiment of the present invention.

The frequency interleaver of 32K FFT mode according to an embodiment ofthe present invention may include a spreader (or a 1-bit toggle switch),a randomizer, a random symbol offset generator (or a symbol offsetgenerator), a modulo operator, and a memory index check block togenerate the above-described interleaving sequence or interleavingaddress. The spreader and the randomizer may be included in theabove-described basic interleaving sequence generator, and the memoryindex check block may be called an address check block. The locations ofthe spreader and the randomizer and the name of the memory index checkblock may vary depending on the intention of a designer.

A description is now given of operation of each block.

The spreader may operate using upper n bits among a total of 15 bits,and may serve as a multiplexer based on a look-up table. In 32K FFTmode, the spreader may be a 1-bit multiplexer (or toggle switch). Therandomizer operates using a PN (or pseudo random bit stream (PRBS))generator and may provide a full randomness effect in interleaving. Asdescribed above, in 32K FFT mode, a PN (or PRBS) generator considering14 bits may be used. The size of the PN (or PRBS) generator may varydepending on the intention of a designer.

The symbol offset generator may generate a symbol offset to be appliedto every OFDM symbol pair. As illustrated in the figure, in the case of32K, the symbol offset may be determined based on a bit sequence of 15bits. The value of the symbol offset is constant for data cellscorresponding to two consecutive symbols included in an OFDM symbolpair. A detailed description thereof has been given above and thus isomitted herein.

The modulo operator may operate if an input value exceeds N_(data) orN_(max). In 32K FFT mode, the maximum value of N_(max) may be 32768.

If a currently generated value exceeds N_(data) or the maximum valueN_(max) of N_(data), the memory index check block may not use an outputvalue of the modulo operator, and may repeatedly operate the spreaderand the randomizer to control the output memory index value (orinterleaving address) not to exceed N_(data) or the maximum valueN_(max) of N_(data).

FIG. 51 illustrates equations showing operation of the frequencyinterleaver of 32K FFT mode according to an embodiment of the presentinvention.

The equation illustrated in an upper part of the figure illustrates aninitial value and a PP of the randomizer included in the above-describedbasic interleaving sequence generator. In this case, the PP may be a14^(th) PP and the initial value may be changed to arbitrary values.

That is, the equation illustrated in the upper part of the figureillustrates a binary word sequence which can be used to define theabove-described basic interleaving sequence.

The equation illustrated in a lower part of the figure illustrates aprocess for calculating an interleaving sequence (or an interleavingaddress) by the frequency interleaver using an output signal of thebasic interleaving sequence generator. As shown in the equation, asymbol offset may be used to output the interleaving sequence, andmodulo operation and address check operation are performed. As describedabove, one symbol offset may be equally applied to data cellscorresponding to every OFDM symbol pair.

As described above, the symbol offset generator according to anembodiment of the present invention may include a k-bit spreader and an(X-k)-bit randomizer. The k-bit spreader operates using a 2^(1c)multiplexer, and may be optimally designed to minimize spreading (or tominimize correlation) between symbols.

The randomizer operates using an N-bit PN generator (or an N-bit PRBSgenerator), and may be designed to provide randomness. The symbol offsetgenerator of 32K FFT mode may include a 0/1/2-bit spreader and a15/14/13-bit random number generator (or PN generator). The sizes of thespreader and the random number generator may vary depending on theintention of a designer.

FIG. 52 illustrates the logical structure of the frequency interleaverof 32K FFT mode according to an embodiment of the present invention.

As described above, the frequency interleaver of 32K FFT mode accordingto an embodiment of the present invention may include a basicinterleaving sequence generator, a symbol offset generator, a modulooperator, and a memory index check block.

Detailed descriptions thereof have been given above and thus are omittedherein.

A description is now given of a frequency interleaver of 32K FFT modeaccording to another embodiment of the present invention. The frequencyinterleaver of 32K FFT mode according to another embodiment of thepresent invention is different from the above-described frequencyinterleaver in that a randomizer of a basic interleaving sequencefurther performs bit shuffling.

FIG. 53 illustrates a frequency interleaver of 32K FFT mode according toanother embodiment of the present invention.

The frequency interleaver of 32K FFT mode according to anotherembodiment of the present invention may include a basic interleavingsequence generator, a symbol offset generator, a modulo operator, and amemory index check block to generate the above-described interleavingsequence or interleaving address, and the basic interleaving sequencegenerator performs bit shuffling. Detailed descriptions of operationsother than bit shuffling have been given above and thus are omittedherein.

Bit shuffling is performed to optimize spreading or randomness, and isdesigned in consideration of N_(data). In 32K FFT mode, the randomizermay use a 14-bit PN generator, and the size of the PN generator mayvary.

FIG. 54 illustrates bit shuffling of the frequency interleaver of 32KFFT mode and equations showing operation of the frequency interleaver,according to an embodiment of the present invention.

In this figure, (a) illustrates the above-described bit shuffling of 32KFFT mode, and (b) illustrates equations showing operation of thefrequency interleaver of 32K FFT mode.

As illustrated in (a), bit shuffling of 32K FFT mode may be used toshuffle bits of registers of a PN generator when a memory index iscalculated. An upper part of (a) illustrates operation of bit shuffling,and a lower part of (a) illustrates an example of bit shuffling in thecase of 14 bits.

As illustrated in the figure, as a result of bit shuffling, a 14-bitbinary word sequence used as a basic interleaving sequence of thefrequency interleaver of 32K FFT mode may be changed to R or R′. Thechanged binary word sequence may be equally applied to data cellscorresponding to every OFDM symbol pair, or applied differently to datacells corresponding to each of two OFDM symbols included in an OFDMsymbol pair.

The equation illustrated in an upper part of (b) shows an initial valueand a PP of the randomizer included in the above-described basicinterleaving sequence generator. In this case, the PP may be a 14^(th)PP and the initial value may be changed to arbitrary values. That is,the equation illustrated in the upper part of the figure illustrates abinary word sequence which can be used to define the above-describedbasic interleaving sequence. The equation illustrated in a lower part of(b) shows a process for calculating an interleaving sequence (or aninterleaving address) by the frequency interleaver using an outputsignal of the basic interleaving sequence generator. As shown in theequation, a symbol offset may be used to output the interleavingsequence, and modulo operation and address check operation areperformed. As described above, one symbol offset may be equally appliedto data cells corresponding to every OFDM symbol pair.

A description is now given of a frequency interleaver of 32K FFT modeaccording to another embodiment of the present invention.

As described above, the frequency interleaver of 32K FFT mode accordingto the present invention may apply the same interleaving sequence orinterleaving address to data (or data cells) corresponding to an OFDMsymbol pair. In this case, the frequency interleaver of 32K FFT modeaccording to an embodiment of the present invention may write data cellscorresponding to an even symbol of the OFDM symbol pair, to memory usingthe interleaving sequence, and read data cells corresponding to an oddsymbol of the OFDM symbol pair, from the memory using the interleavingsequence. In addition, the write operation and the read operation of thefrequency interleaver according to an embodiment of the presentinvention are consecutively performed on input data cells and may beperformed simultaneously. That is, if data cells corresponding to an oddsymbol are input after data cells corresponding to an even symbol arerandomly written to memory, the frequency interleaver according to anembodiment of the present invention may linearly read the written datacells corresponding to the even symbol and, at the same time, linearlywrite the input data cells corresponding to the odd symbol to thememory. After that, the data cells corresponding to the odd symbol whichare written to the memory may be randomly read. In addition, since thefrequency interleaver according to an embodiment of the presentinvention operates for data cells corresponding to an OFDM symbol pair,the number of symbols corresponding to OFDM symbols in a signal frame isalways an even number.

The frequency interleaver of 32K FFT mode according to the presentinvention may use a different interleaving sequence per data cellscorresponding to every OFDM symbol pair, thereby improving randomnessand maximizing diversity performance Specifically, the frequencyinterleaver of 32K FFT mode according to the present invention maygenerate a different interleaving sequence per data cells correspondingto every OFDM symbol pair by rotating a basic interleaving sequence by asymbol offset. In this case, the symbol offset may be generateddifferently per data cells corresponding to every OFDM symbol pair.Accordingly, since the transmitter linearly reads data cellscorresponding to an even symbol of an OFDM symbol pair and linearlywrites data cells corresponding to an odd symbol of the OFDM symbol pairin a frequency interleaving process, the broadcast signal receptionapparatus or the frequency deinterleaver included in the broadcastsignal reception apparatus according to an embodiment of the presentinvention may perform frequency deinterleaving using a single memory.The maximum memory size required in this case may be 32K.

FIG. 55 illustrates an equation showing operation of the frequencyinterleaver of 32K FFT mode according to the present invention.

A block of an upper part of the figure illustrates an equation showingfrequency interleaving input and output for data cells corresponding toan even symbol and data cells corresponding to an odd symbol of an OFDMsymbol pair.

A left part shows output data obtained by performing frequencyinterleaving (interleaved vector) and a right part shows input datacells for frequency interleaving (interleaver input vector). In thefigure, X_(m,l,p) may indicate a cell index p to be mapped to an OFDMsymbol of an m^(th) frame, and X_(m,l,H(p)) indicates that the cellindex p to be mapped to the OFDM symbol of the m^(th) frame is readbased on an interleaving address (or interleaving sequence).

That is, the equation illustrated in the figure illustrates that datacells corresponding to an even symbol of an OFDM symbol pair are writtento memory using an interleaving sequence, and data cells correspondingto an odd symbol are read based on the interleaving sequence.

A block of a lower part of the figure illustrates an interleavingsequence applied per OFDM symbol pair. As illustrated in the figure, theinterleaving sequence may be calculated using a symbol offset and thevalue of Nmax. The size of Nmax is as described above.

A description is now given of a frequency interleaver of 16K FFT modeaccording to another embodiment of the present invention.

The frequency interleaver of 16K FFT mode according to the presentinvention may apply the same interleaving sequence to cellscorresponding to an OFDM symbol pair. In this case, like the frequencyinterleaver of 32K FFT mode, the frequency interleaver of 16K FFT modeaccording to an embodiment of the present invention may write data cellscorresponding to an even symbol of the OFDM symbol pair, to memory usingthe interleaving sequence, and read data cells corresponding to an oddsymbol of the OFDM symbol pair, from the memory using the interleavingsequence. Operation of the frequency interleaver of 16K FFT mode is thesame as the operation of the frequency interleaver of 32K FFT mode, andthus a detailed description thereof is omitted herein. As a result, thefrequency interleaver of 16K FFT mode according to the present inventionmay enable frequency deinterleaving using a single memory at thereceiver side, and the maximum memory size required in this case may be16K.

In addition, the frequency interleaver of 16K FFT mode according to anembodiment of the present invention may perform frequency interleavingby applying a different interleaving sequence per data cellscorresponding to each OFDM symbol. In this case, the frequencyinterleaver of 16K FFT mode according to an embodiment of the presentinvention may apply the interleaving sequence to randomly read datacells corresponding to an input symbol from memory, and there is norestriction on the number of OFDM symbols in a frame. In addition, evenwhen a different interleaving sequence is applied per data cellscorresponding to each OFDM symbol, the frequency interleaver of 16K FFTmode according to the present invention may generate the differentinterleaving sequence per data cells corresponding to each OFDM symbolby rotating a basic interleaving sequence by a symbol offset. In thiscase, the symbol offset may be generated differently per data cellscorresponding to every OFDM symbol pair.

In this case, the receiver side may perform frequency deinterleavingusing double memories. The maximum memory size required in this case maybe 32K.

FIG. 56 illustrates equations showing operation of the frequencyinterleaver of 16K FFT mode according to the present invention.

In this figure, (a) illustrates an equation showing operation in a casewhen the frequency interleaver of 16K FFT mode according to the presentinvention applies the same interleaving sequence to data cellscorresponding to an OFDM symbol pair, and showing frequency interleavinginput and output for data cells corresponding to an even symbol and datacells corresponding to an odd symbol of an OFDM symbol pair.

In this figure, (b) illustrates an equation showing frequencyinterleaving input and output in a case when the frequency interleaverof 16K FFT mode according to the present invention performs readoperation by applying a different interleaving sequence per data cellscorresponding to each OFDM symbol.

Specifically, a left part of the equation shows output data obtained byperforming frequency interleaving (interleaved vector) and a right partshows input data cells for frequency interleaving (interleaver inputvector).

In the figure, X_(m,l,p) may indicate a cell index p to be mapped to anOFDM symbol of an m^(th) frame, and X_(m,l,H(p)) indicates that the cellindex p to be mapped to the OFDM symbol of the m^(th) frame is readbased on an interleaving address (or interleaving sequence).

Accordingly, the equation illustrated in (a) shows that data cellscorresponding to an even symbol of an OFDM symbol pair are written tomemory using an interleaving sequence, and data cells corresponding toan odd symbol are read based on the interleaving sequence.

In addition, the equation illustrated in (b) shows a process for readingdata cells corresponding to each OFDM symbol using an interleavingsequence.

A block of a lower part of (a) or (b) shows an interleaving sequenceapplied per OFDM symbol pair. As illustrated in the figure, theinterleaving sequence may be calculated using a symbol offset and thevalue of Nmax. The size of Nmax is as described above.

A description is now given of a frequency interleaver of 8K FFT modeaccording to another embodiment of the present invention.

The frequency interleaver of 8K FFT mode according to the presentinvention may apply a different interleaving sequence per data cellscorresponding to each OFDM symbol. In this case, the frequencyinterleaver of 8K FFT mode according to an embodiment of the presentinvention may apply the interleaving sequence to randomly read datacells corresponding to an input symbol from memory, and there is norestriction on the number of OFDM symbols in a frame. In addition, evenwhen a different interleaving sequence is applied per data cellscorresponding to each OFDM symbol, the frequency interleaver of 8K FFTmode according to the present invention may generate the differentinterleaving sequence per data cells corresponding to each OFDM symbolby rotating a basic interleaving sequence by a symbol offset. In thiscase, the symbol offset may be generated differently per data cellscorresponding to every OFDM symbol pair.

In addition, the receiver side may perform frequency deinterleavingusing double memories. The maximum memory size required in this case maybe 16K.

FIG. 57 illustrates an equation showing operation of the frequencyinterleaver of 8K FFT mode according to the present invention.

The equation illustrated in an upper part of the figure illustratesfrequency interleaving input and output in a case when the frequencyinterleaver of 8K FFT mode according to the present invention performsread operation by applying a different interleaving sequence per datacells corresponding to each OFDM symbol.

Specifically, a left part of the equation shows output data obtained byperforming frequency interleaving (interleaved vector) and a right partshows input data cells for frequency interleaving (interleaver inputvector).

In the figure, X_(m,l,H(p)) indicates that a cell index p to be mappedto an OFDM symbol of an m^(th) frame is read based on an interleavingaddress (or interleaving sequence).

Accordingly, the equation illustrated in the upper part of the figureillustrates a process for reading data cells corresponding to each OFDMsymbol using an interleaving sequence.

A block of a lower part of the figure illustrates an interleavingsequence applied per OFDM symbol pair. As illustrated in the figure, theinterleaving sequence may be calculated using a symbol offset and thevalue of Nmax. The size of Nmax is as described above.

FIG. 58 illustrates equations showing input and output of a frequencyinterleaver based on each FFT mode.

The equation illustrated in a block of an upper part of the figureillustrates the relationship between input and output of the frequencyinterleaver of 32K FFT mode and 16K FFT mode, and shows a case in whichone interleaving sequence is applied to data cells corresponding to oneOFDM symbol pair.

The equation illustrated in a block of a lower part of the figureillustrates the relationship between input and output of the frequencyinterleaver of 16K FFT mode and 8K FFT mode, and shows a case in whichone interleaving sequence is applied to data cells corresponding to oneOFDM symbol.

As described above, a left part shows an interleaved vector output fromthe frequency interleaver and a right part shows an input data vector(or an input vector) input to the frequency interleaver.

FIG. 59 illustrates a frequency interleaver of 32K FFT mode according toanother embodiment of the present invention.

As described above, the frequency interleaver of 32K FFT mode mayinterleave an input OFDM symbol pair using an interleaving sequence orinterleaving address. The frequency interleaver of 32K FFT modeillustrated in FIG. 59 may include a basic interleaving sequencegenerator, a symbol offset generator, a modulo operator, and an addresscheck block to generate the above-described interleaving sequence orinterleaving address. FIG. 59 corresponds to another embodiment of thefrequency interleaver described above in relation to FIGS. 50, 52, and53. A description is now given of each block.

The basic interleaving sequence generator may include a basic randomaddress generator and a wire permutation block. The basic random addressgenerator may include a 1-bit toggle switch and a 14-bit PN generatorand may operate to generate quasi-randomness in interleaving. The wirepermutation block may change the order of bits when a decimal address isgenerated using the value of a PRBS register. In this case, the wirepermutation block may change the order of bits using a preset wirepermutation table. In 32K FFT mode, the same wire permutation table maybe used for data cells corresponding to symbols included in an OFDMsymbol pair. A detailed description thereof will be given below.

The symbol offset generator operates in units of an OFDM symbol pair andmay generate a symbol offset for cyclically shifting a basicinterleaving sequence output from the basic interleaving sequencegenerator.

The modulo operator operates if output data exceeds Nmax, and the valueof Nmax in the case of 32K may be 32768.

The address check block and a PRBS controller do not use but ignore anoutput value H_(i)(p), i.e., an interleaving sequence (or interleavingaddress), of 15 bits if the output value is greater than an input datavector size Ndata, and may repeatedly control operation of the basicinterleaving sequence generator to allow the interleaving address valuenot to exceed Nmax.

As described above, the modulo operator may operate prior to the addresscheck block. This serves to allow the receiver to perform deinterleavingusing a single memory even when the OFDM symbol pair has different sizesof data vectors (or data cells).

FIG. 60 illustrates a frequency interleaver of 16K FFT mode according toanother embodiment of the present invention.

As described above, the frequency interleaver of 16K FFT mode mayinterleave an input OFDM symbol pair or data cells corresponding to aninput OFDM symbol using an interleaving sequence or interleavingaddress. The frequency interleaver of 16K FFT mode illustrated in FIG.60 may include a basic interleaving sequence generator, a symbol offsetgenerator, a modulo operator, and an address check block to generate theabove-described interleaving sequence or interleaving address. FIG. 60corresponds to another embodiment of the frequency interleaver describedabove in relation to FIGS. 43, 45, and 46. A description is now given ofeach block.

The basic interleaving sequence generator may include a basic randomaddress generator and a wire permutation block. The basic random addressgenerator may include a 1-bit toggle switch and a 13-bit PN generatorand may operate to generate quasi-randomness in interleaving. The wirepermutation block may change the order of bits when a decimal address isgenerated using the value of a PRBS register. In this case, the wirepermutation block may change the order of bits using a preset wirepermutation table. In 16K FFT mode, the same wire permutation table maybe used for data cells corresponding to symbols included in an OFDMsymbol pair, or a different wire permutation table may be used per datacells corresponding to each symbol included in an OFDM symbol pair. Adetailed description thereof will be given below.

The symbol offset generator operates in units of an OFDM symbol pair andmay generate a symbol offset for cyclically shifting a basicinterleaving sequence output from the basic interleaving sequencegenerator.

The modulo operator operates if output data exceeds Nmax, and the valueof Nmax in the case of 16K may be 16384.

The address check block and a PRBS controller do not use but ignore anoutput value H_(l)(p), i.e., an interleaving sequence (or interleavingaddress), of 14 bits if the output value is greater than an input datavector size Ndata, and may repeatedly control operation of the basicinterleaving sequence generator to allow the interleaving address valuenot to exceed Nmax.

As described above, the modulo operator may operate prior to the addresscheck block. This serves to allow the receiver to perform deinterleavingusing a single memory even when the OFDM symbol pair has different sizesof data vectors (data cells).

FIG. 61 illustrates a frequency interleaver of 8K FFT mode according toanother embodiment of the present invention.

As described above, the frequency interleaver of 8K FFT mode mayinterleave an input symbol using an interleaving sequence orinterleaving address. The frequency interleaver of 8K FFT modeillustrated in FIG. 61 may include a basic interleaving sequencegenerator, a symbol offset generator, a modulo operator, and an addresscheck block to generate the above-described interleaving sequence orinterleaving address. FIG. 61 corresponds to another embodiment of thefrequency interleaver described above in relation to FIGS. 36, 38, and39. A description is now given of each block.

The basic interleaving sequence generator may include a basic randomaddress generator and a wire permutation block. The basic random addressgenerator may include a 1-bit toggle switch and a 12-bit PN generatorand may operate to generate quasi-randomness in interleaving. The wirepermutation block may change the order of bits when a decimal address isgenerated using the value of a PRBS register. In this case, the wirepermutation block may change the order of bits using a preset wirepermutation table. In 8K FFT mode, a different wire permutation tablemay be used per data cells corresponding to each symbol included in anOFDM symbol pair. A detailed description thereof will be given below.

The symbol offset generator operates in units of an OFDM symbol pair andmay generate a symbol offset for cyclically shifting a basicinterleaving sequence output from the basic interleaving sequencegenerator.

The modulo operator operates if output data exceeds Nmax, and the valueof Nmax in the case of 8K may be 8192.

The address check block and a PRBS controller do not use but ignore anoutput value H_(l)(p), i.e., an interleaving sequence (or interleavingaddress), of 13 bits if the output value is greater than an input datavector size Ndata, and may repeatedly control operation of the basicinterleaving sequence generator to allow the interleaving address valuenot to exceed Nmax.

As described above, the modulo operator may operate prior to the addresscheck block. This serves to allow the receiver to perform deinterleavingusing a single memory even when the OFDM symbol pair has different sizesof data vectors.

FIG. 62 illustrates wire permutation tables according to embodiments ofthe present invention.

The first row of each table shows bit positions of an input bitsequence, and the second and third rows show bit positions changedthrough permutation.

In this figure, (a) illustrates an exemplary wire permutation table in32K FFT mode, which is equally applied to data cells corresponding tosymbols included in an input OFDM symbol pair.

In this figure, (b) illustrates an exemplary wire permutation table in16K FFT mode, which is equally applied to data cells corresponding tosymbols included in an input OFDM symbol pair.

In this figure, (c) illustrates another exemplary wire permutation tablein 16K FFT mode, which is applied differently to data cellscorresponding to each input OFDM symbol pair. As illustrated in thefigure, the second row shows changed bit positions of data cellscorresponding to an even symbol of the input OFDM symbol pair, and thethird row shows changed bit positions of data cells corresponding to anodd symbol of the input OFDM symbol pair.

In this figure, (d) illustrates an exemplary wire permutation table in8K FFT mode, which is applied differently to data cells corresponding toeach input OFDM symbol pair. A description of this table is the same asthat of the above table of (c), and thus is omitted herein.

Each bit position may vary depending on the intention of a designer.

FIG. 63 illustrates an equation showing operation of the basicinterleaving sequence generator according to an embodiment of thepresent invention.

As described above, the basic interleaving sequence generator accordingto an embodiment of the present invention may generate a binary word R′having a different size of bits per FFT mode. FIG. 63 illustrates anequation showing a process for generating the binary word. This may bechanged to an arbitrary PRBS. The basic interleaving sequence generatoraccording to an embodiment of the present invention may generate a basicinterleaving sequence by performing wire permutation and toggling on thegenerated binary word R′.

FIG. 64 illustrates an equation showing operation of the symbol offsetgenerator according to an embodiment of the present invention.

As described above, the symbol offset generator according to anembodiment of the present invention may generate a symbol offset foreach OFDM symbol pair, and the generated symbol offset has a constantvalue for data cells corresponding to two symbols included in the OFDMsymbol pair. In addition, the symbol offset generator may generate abinary word G_(k) having a specific value per FFT mode. This may bechanged to an arbitrary PRBS.

FIG. 65 illustrates equations showing an interleaving address accordingto an embodiment of the present invention.

The frequency interleaver according to the present invention maygenerate an interleaving address H_(l)(p) using the above-describedbasic interleaving sequence and the symbol offset.

The equation illustrated in an upper part of the figure illustrates aprocess for generating the interleaving address, and the equationillustrated in a lower part of the figure illustrates the symbol offset.These equations may vary depending on the intention of a designer.

A description is now given of a frequency interleaver of 16K FFT modeaccording to another embodiment of the present invention.

The frequency interleaver of 16K FFT mode according to the presentinvention may apply a different interleaving sequence per data cellscorresponding to each OFDM symbol. In this case, the frequencyinterleaver of 16K FFT mode according to an embodiment of the presentinvention may apply the interleaving sequence to randomly read datacells corresponding to an input symbol from memory, and there is norestriction on the number of OFDM symbols in a frame. In addition, evenwhen a different interleaving sequence is applied per OFDM symbol, thefrequency interleaver of 16K FFT mode according to the present inventionmay generate the different interleaving sequence per OFDM symbol byrotating a basic interleaving sequence by a symbol offset. In this case,the symbol offset may have a constant value for cells corresponding toevery OFDM symbol pair.

As a result, the frequency interleaver of 16K FFT mode according to thepresent invention may enable frequency deinterleaving using a singlememory at the receiver side, and the maximum memory size required inthis case may be 16K.

FIG. 66 illustrates an equation showing a frequency interleaver of 16KFFT mode according to another embodiment of the present invention.

FIG. 66 corresponds to another embodiment of the frequency interleaverof 16K FFT mode, which is described above in relation to FIG. 56. Adescription is now given of each block. This figure illustrates anequation showing frequency interleaving input and output in a case whenthe frequency interleaver of 16K FFT mode according to the presentinvention applies a different interleaving sequence per data cellscorresponding to each OFDM symbol to randomly write the same to memory.

Specifically, a left part of the equation shows output data obtained byperforming frequency interleaving (interleaved vector) and a right partshows input data cells for frequency interleaving (interleaver inputvector).

In the figure, X_(m,l,p) indicates a cell index p in an OFDM symbol ofan m^(th) frame.

As illustrated in the figure, the interleaving sequence may becalculated using a symbol offset and the value of Nmax. The size of Nmaxis as described above.

In addition, the receiver side may perform frequency deinterleavingusing double memories. The maximum memory size required in this case maybe 32K.

A description is now given of a frequency interleaver of 8K FFT modeaccording to another embodiment of the present invention.

The frequency interleaver of 8K FFT mode according to the presentinvention may apply the same interleaving sequence to data cellscorresponding to an OFDM symbol pair. In this case, like theabove-described frequency interleaver of 32K FFT mode, the frequencyinterleaver of 8K FFT mode according to an embodiment of the presentinvention may use the interleaving sequence to write data cellscorresponding to an even symbol of the OFDM symbol pair, and use theinterleaving sequence to read data cells corresponding to an odd symbolof the OFDM symbol pair. Operation of the frequency interleaver of 8KFFT mode is the same as the operation of the frequency interleaver of32K FFT mode, and thus a detailed description thereof is omitted herein.As a result, the frequency interleaver of 8K FFT mode according to thepresent invention may enable frequency deinterleaving using a singlememory at the receiver side, and the maximum memory size required inthis case may be 8K.

Furthermore, the frequency interleaver of 8K FFT mode according to anembodiment of the present invention may apply the interleaving sequenceto randomly write data cells corresponding to an input symbol, and thereis no restriction on the number of OFDM symbols in a frame. In addition,even when a different interleaving sequence is applied per OFDM symbol,the frequency interleaver of 8K FFT mode according to the presentinvention may generate the different interleaving sequence per OFDMsymbol by rotating a basic interleaving sequence by a symbol offset. Inthis case, the symbol offset may be generated differently per OFDMsymbol pair.

In this case, the receiver side may perform frequency deinterleavingusing double memories, and the maximum memory size required in this casemay be 16K.

FIG. 67 illustrates equations showing operation of the frequencyinterleaver of 8K FFT mode according to another embodiment of thepresent invention.

FIG. 67 corresponds to another embodiment of the frequency interleaverof 8K FFT mode, which is described above in relation to FIG. 57.

In this figure, (a) illustrates an equation showing operation in a casewhen the frequency interleaver of 8K FFT mode according to the presentinvention applies the same interleaving sequence to data cellscorresponding to an OFDM symbol pair, and showing frequency interleavinginput and output for data cells corresponding to an even symbol and datacells corresponding to an odd symbol of an OFDM symbol pair.

In this figure, (b) illustrates an equation showing frequencyinterleaving input and output in a case when the frequency interleaverof 8K FFT mode according to the present invention performs writeoperation by applying a different interleaving sequence per data cellscorresponding to each OFDM symbol.

Specifically, a left part of the equation shows output data obtained byperforming frequency interleaving (interleaved vector) and a right partshows input data cells for frequency interleaving (interleaver inputvector).

In the figure, X_(m,l,p) may indicate a cell index p to be mapped to anOFDM symbol of an m^(th) frame, and X_(m,l,H(p)) indicates that the cellindex p to be mapped to the OFDM symbol of the m^(th) frame is readbased on an interleaving address (or interleaving sequence).

Accordingly, the equation illustrated in (a) shows that data cellscorresponding to an even symbol of an OFDM symbol pair are written tomemory using an interleaving sequence, and data cells corresponding toan odd symbol are read based on the interleaving sequence.

In addition, the equation illustrated in (b) shows a process for writingdata cells corresponding to each OFDM symbol using an interleavingsequence.

A block of a lower part of (a) or (b) shows an interleaving sequenceapplied per OFDM symbol pair. As illustrated in the figure, theinterleaving sequence may be calculated using a symbol offset and thevalue of Nmax. The size of Nmax is as described above.

FIG. 68 illustrates an equation showing input and output of a frequencyinterleaver based on each FFT mode.

The equation illustrated in a block of the figure illustrates therelationship between input and output of the frequency interleaver of16K FFT mode and 8K FFT mode, and shows a case in which one interleavingsequence is applied to data cells corresponding to one OFDM symbol. Asdescribed above, a left part shows an interleaved vector output from thefrequency interleaver and a right part shows an input data vector (or aninput vector) input to the frequency interleaver.

FIG. 69 illustrates equations showing operation of the frequencyinterleaver based on an FFT mode according to an embodiment of thepresent invention.

FIG. 69 corresponds to another embodiment of the above-describedequations showing operation of the frequency interleaver of 32K, 16K, or8K FFT mode. In this figure, (a) illustrates an equation showingoperation of the frequency interleaver of 32K FFT mode according to anembodiment of the present invention, and (b) illustrates an equationshowing operation of the frequency interleaver of 16K or 8K FFT modeaccording to an embodiment of the present invention.

A left part of the equation illustrated in (a) or (b) shows output dataobtained by performing frequency interleaving (interleaved data cellscorresponding to an OFDM symbol) and a right part shows input data cellsfor frequency interleaving.

Specifically, (a) illustrates an equation in a case when the frequencyinterleaver of 32K FFT mode according to the present invention appliesthe same interleaving sequence or interleaving address to data (or datacells) corresponding to an OFDM symbol pair. As described above, thefrequency interleaver of 32K FFT mode according to an embodiment of thepresent invention may write data cells corresponding to an even symbolof the OFDM symbol pair, to memory using the interleaving sequence, andread data cells corresponding to an odd symbol of the OFDM symbol pair,from the memory using the interleaving sequence. In this case, thenumber of symbols corresponding to OFDM symbols in a signal frame isalways an even number.

The frequency interleaver of 32K FFT mode according to the presentinvention may use a different interleaving sequence per data cellscorresponding to every OFDM symbol pair, thereby improving randomnessand maximizing diversity performance Specifically, the frequencyinterleaver of 32K FFT mode according to the present invention maygenerate a different interleaving sequence per data cells correspondingto every OFDM symbol pair by rotating a basic interleaving sequence by asymbol offset. In this case, the symbol offset may be generateddifferently per data cells corresponding to every OFDM symbol pair.

Accordingly, since the transmitter linearly reads data cellscorresponding to an even symbol of an OFDM symbol pair and linearlywrites data cells corresponding to an odd symbol of the OFDM symbol pairin a frequency interleaving process, the broadcast signal receptionapparatus or the frequency deinterleaver included in the broadcastsignal reception apparatus according to an embodiment of the presentinvention may perform frequency deinterleaving using a single memory.The maximum memory size required in this case may be 32K.

In this figure, (b) shows that the frequency interleaver of 16K or 8KFFT mode according to the present invention may perform frequencyinterleaving by applying a different interleaving sequence per datacells corresponding to each OFDM symbol. In this case, the frequencyinterleaver of 16K or 8K FFT mode according to an embodiment of thepresent invention may apply the interleaving sequence to randomly readdata cells corresponding to an input symbol from memory, and there is norestriction on the number of OFDM symbols in a frame. In addition, evenwhen a different interleaving sequence is applied per data cellscorresponding to each OFDM symbol, the frequency interleaver of 16K or8K FFT mode according to the present invention may generate thedifferent interleaving sequence per data cells corresponding to eachOFDM symbol by rotating a basic interleaving sequence by a symboloffset. In this case, the symbol offset may be generated differently perdata cells corresponding to every OFDM symbol pair.

In this case, the receiver side may perform frequency deinterleavingusing double memories. The maximum memory size required in this case maybe 32K or 16K.

FIG. 70 illustrates an equation showing an interleaving addressaccording to another embodiment of the present invention.

FIG. 70 corresponds to another embodiment of the equation showing aninterleaving address, which is described above in relation to FIG. 65,and illustrates a process for generating an interleaving addressH_(l)(p) using the above-described basic interleaving sequence and thesymbol offset. This equation may vary depending on the intention of adesigner. A detailed description thereof has been given above and thusis omitted herein.

FIG. 71 illustrates a frequency deinterleaving process according to anembodiment of the present invention.

Specifically, FIG. 71 illustrates a frequency deinterleaving process atthe receiver side in a case when a frequency interleaver of 16K or 8KFFT mode has performed frequency interleaving by applying a differentinterleaving sequence per data cells corresponding to each OFDM symbol.In this case, since frequency deinterleaving may be performed usingdouble memories as described above, the receiver side may performfrequency deinterleaving in a ping-pong structure. A basic interleavingsequence used in this case is the same as that used at the transmitterside.

A description is now given of the structure of a signal frame of thebroadcast signal transmission/reception apparatus for future broadcastservices, according to an embodiment of the present invention.

FIG. 72 illustrates the logical structure of a signal frame according toan embodiment of the present invention.

FIG. 72 corresponds to another embodiment of the frame described abovein relation to FIGS. 1 to 29, and the logical structure of the signalframe according to an embodiment of the present invention may include abootstrap, preamble symbols (L1 signaling), and payload data symbols (ordata symbols).

The bootstrap illustrated in FIG. 72 may correspond to theabove-described preamble, the preamble symbols illustrated in FIG. 72may correspond to the above-described FSS, and the payload data symbolsmay correspond to the normal data symbols. In addition, L1 signaling maycorrespond to the above-described PLS1 or PLS2 signaling.

The bootstrap according to an embodiment of the present invention may beinserted at a front part of the signal frame, and may be processed tohave robustness compared to the preamble or the payload data in such amanner that the broadcast signal reception apparatus can detect thecorresponding signal frame. In addition, the bootstrap according to anembodiment of the present invention may carry essential broadcast systeminformation and essential information for accessing a correspondingbroadcast system. The bootstrap according to an embodiment of thepresent invention may include Emergency Alert System (EAS) wake-upinformation, system information, preamble structure indicatorinformation, information for future extension, etc.

The preamble structure indicator information according to an embodimentof the present invention may include an FFT mode of the preamble, thenumber of active carriers (NoA) of the preamble, the number of OFDMsymbols included in the preamble, etc.

As illustrated in the figure, the above-described frequency interleavingprocess is performed on the preamble symbols and the data symbolsaccording to an embodiment of the present invention (FI ON), butfrequency interleaving is not performed on the bootstrap (FI OFF).

A description is now given of frequency interleaving of preamble symbolsaccording to an embodiment of the present invention.

FIG. 73 illustrates the structure of preamble symbols according to anembodiment of the present invention.

The preamble symbols according to an embodiment of the present inventionmay include one or more OFDM symbols based on the number of bits of L1signaling information to be transmitted. The L1 signaling information tobe transmitted using the preamble symbols may be mapped to activecarriers of the OFDM symbols, and then frequency-interleaved. In thiscase, input data of a frequency interleaver may be preamble cellscorresponding to the OFDM symbols.

Parameters of the preamble symbols have arbitrary fixed values unlikedata symbols.

Therefore, the broadcast signal reception apparatus according to anembodiment of the present invention may process the preamble symbolswithout acquiring signaling information of the preamble from abootstrap, and may reduce a service acquisition time including a channelscan time by rapidly acquiring the L1 signaling information carried bythe preamble symbols. In addition, the possibility of FFT/GI acquisitionfailure may be minimized even in a poor channel environment and thusbroadcast signal reception performance may be improved.

Parameters of the preamble symbols and preconditions for using theparameters according to an embodiment of the present invention are asdescribed below.

Initially, the smallest FFT mode (e.g., 8K FFT mode) may be applied tothe preamble symbols to improve flexibility in operating a broadcastsignal system. In addition, the NoA of the preamble symbols may be fixedto allow the receiver to detect the preamble symbols without signalingthe bootstrap. Furthermore, the number of preamble symbols may bedetermined in consideration of the relationship between the FFT mode ofthe preamble symbols and the FFT mode of the data symbols.

If the FFT mode of the preamble symbols is different from the FFT modeof the data symbols, the number of preamble symbols is restricted to aneven number. This serves to consecutively frequency-deinterleave thedata symbols using a single memory by the broadcast signal receptionapparatus.

If the FFT mode of the preamble symbols is the same as the FFT mode ofthe data symbols, the number of preamble symbols is not restricted. Thatis, an odd or even number of preamble symbols may be used irrespectiveof the data symbols.

FIG. 74 illustrates a frequency interleaving process of preamble symbolsaccording to an embodiment of the present invention.

Specifically, FIG. 74 illustrates a frequency interleaving processapplied to preamble cells corresponding to the preamble symbols in acase when the FFT mode of the preamble symbols is different from the FFTmode of the data symbols.

In this case, the number of preamble symbols described above in relationto FIG. 73 may be an even number. The frequency interleaver according toan embodiment of the present invention may perform frequencyinterleaving by regarding preamble cells corresponding to an OFDM symbolpair including two consecutive symbols, as one group.

As illustrated in a lower part of the figure, the frequency interleaveraccording to an embodiment of the present invention may write preamblecells corresponding to an even symbol of an OFDM symbol pair, to memoryusing an interleaving sequence, and read preamble cells corresponding toan odd symbol of the OFDM symbol pair, from memory using theinterleaving sequence. In addition, the write operation and the readoperation of the frequency interleaver according to an embodiment of thepresent invention are consecutively performed on input preamble cellsand may be performed simultaneously.

That is, if preamble cells corresponding to an odd symbol (the secondsymbol) are input after preamble cells corresponding to an even symbol(the first symbol) are randomly written to memory, the frequencyinterleaver according to an embodiment of the present invention maylinearly read the written preamble cells corresponding to the evensymbol and, at the same time, linearly write the input preamble cellscorresponding to the odd symbol to the memory. After that, the preamblecells corresponding to the odd symbol which are written to the memorymay be randomly read.

As a result, the broadcast signal reception apparatus or the frequencydeinterleaver included in the broadcast signal reception apparatusaccording to an embodiment of the present invention may performfrequency deinterleaving using a single memory. This principle isequally applied to a frequency interleaving process of the data symbols.

FIG. 75 illustrates a frequency interleaving process of preamble symbolsaccording to another embodiment of the present invention.

Specifically, FIG. 75 illustrates a frequency interleaving processapplied to preamble cells corresponding to the preamble symbols in acase when the FFT mode of the preamble symbols is the same as the FFTmode of the data symbols.

In this case, it is assumed that the preamble symbols use the sameparameters (FFT/GI/NoA) as the data symbols, and the broadcast signalreception apparatus acquires parameter information of the preamblesymbols and information about the number of preambles from the bootstrap(preamble structure indicator information). In addition, as describedabove in relation to FIG. 73, the number of preamble symbols may be aneven number or an odd number.

FIG. 75 illustrates the frequency interleaving process in a case whenthe number of preamble symbols is an even number. Therefore, thefrequency interleaver according to an embodiment of the presentinvention may perform frequency interleaving by regarding preamble cellscorresponding to an OFDM symbol pair including two consecutive symbols,as one group. A detailed description thereof has been given above inrelation to FIG. 74 and thus is omitted herein.

FIG. 76 illustrates the signaling structure of the logical structure ofa signal frame according to an embodiment of the present invention.

Specifically, FIG. 76 illustrates signaling information/content to betransmitted in the order of a bootstrap, preamble symbols, and datasymbols for frequency interleaving and frequency deinterleavingaccording to an embodiment of the present invention, and an overalloperation mechanism thereof. If different FFT modes are applied to thedata symbols according to the present invention, a set of data symbolsto be processed in the same FFT mode may be called a partition.

The signal frame according to an embodiment of the present invention mayincludes at least one partition and the partition can be referred as asub frame (or sub-frame). It can be changed by a designer's intention.

FIG. 76 illustrates the logical structure of the signal frame in a casewhen the same or different FFT modes are applied to the data symbols.

As described above, the bootstrap according to an embodiment of thepresent invention carries information required to acquire the preamblesymbols by the broadcast signal reception apparatus. Specifically, thebootstrap according to an embodiment of the present invention may carryFFT mode information of the preamble symbols, the NoA of the preamblesymbols, the number of preamble symbols, etc.

The preamble symbols according to an embodiment of the present inventionmay carry information required to detect the data symbols by thebroadcast signal reception apparatus. Specifically, the preamble symbolsaccording to an embodiment of the present invention may include thenumber of partitions, FFT mode information per partition, the NoA ofdata symbols included in each partition, the number of data symbols pereach partition, start symbol (or cell) information of each partition, asame FFT indicator indicating the location (or timing) of the same FFTmode within the signal frame, etc. The above-described information itemsmay dynamically vary every signal frame.

FIG. 77 illustrates the structure of payload data of a signal frameaccording to an embodiment of the present invention.

In this figure, (a) illustrates a payload data structure in a case whenthe same FFT mode is applied to payload data, i.e., data symbols, and(b) illustrates a payload data structure in a case when various FFTmodes are applied to data symbols.

In the present invention, a signal frame illustrated in (a) may becalled a single FFT signal frame, and a signal frame illustrated in (b)may be called a mixed-FFT-mode signal frame. The names thereof may varydepending on the intention of a designer.

In the case of (a), data symbols in one signal frame have the same OFDMsymbol structure, and have the same parameters (e.g., FFT mode, GIlength, NoA, pilot pattern, etc.). As described above, the parametersfor the data symbols are transmitted using preamble symbols.

If the frequency interleaver according to an embodiment of the presentinvention operates per data cells corresponding to an OFDM symbol pair,the number of data symbols should be defined as an even number.Accordingly, the number of data symbols may be defined as describedbelow based on the relationship between the FFT mode of the preamblesymbols and the FFT mode of the data symbols.

If the FFT mode of the preamble symbols is different from the FFT modeof the data symbols, the number of data symbols should be an evennumber.

If the FFT mode of the preamble symbols is the same as the FFT mode ofthe data symbols, a sum of the number of preamble symbols and the numberof data symbols should be an even number. As a result, the number ofdata symbols may be an even number or an odd number based on the numberof preamble symbols.

In the case of (b), data symbols in one signal frame have a plurality ofOFDM symbol structures, and have different parameters (e.g., FFT mode,GI length, NoA, pilot pattern, etc.) based on the symbol structure.Since a set of data symbols having the same OFDM structure in the mixedFFT frame may be defined as a partition, one mixed FFT frame may includea plurality of partitions.

Accordingly, as illustrated in the figure, parameters (e.g., FFT mode,GI length, NoA, pilot pattern, etc.) may be independently set for eachpartition, and the preamble symbols may include information about thelocation and structure of each partition, information about the numberof data symbols, etc. In addition, the partitions of various FFT modesmay be transmitted in a signal frame having a Time Division Multiplexing(TDM), Layered Division Multiplexing (LDM), or Frequency DivisionMultiplexing (FDM) structure, and a partition of each FFT mode may bedefined as a set of OFDM symbols having a specific GI.

Different FFT modes may be defined to process broadcast servicesappropriate for a variety of broadcast signal reception apparatuses,e.g., a mobile broadcast signal reception apparatus and a fixedbroadcast signal reception apparatus. Accordingly, if a target broadcastservice or a target broadcast signal reception apparatus is determinedper FFT mode, the broadcast signal reception apparatus may acquire andprocess only a partition of a broadcast service appropriate therefor,and thus a power saving effect of the receiver may be increased.

Frequency deinterleaving of the broadcast signal reception apparatusaccording to an embodiment of the present invention may be performed asdescribed below based on the relationship between the number of datasymbols of each partition and the number of preamble symbols in a casewhen the FFT mode of the preamble symbols is the same as or differentfrom the FFT mode of the data symbols.

When the FFT mode of the preamble symbols is the same as the FFT mode ofthe data symbols of the first partition, if the number of preamblesymbols and the number of data symbols of each partition are evennumbers, deinterleaving may be performed as described below.

The broadcast signal reception apparatus may consecutively deinterleavethe preamble symbols and the data symbols using a single memory (maximumvalue: 32K). Particularly, since the broadcast signal receptionapparatus may perform deinterleaving using a single memory even whenpartitions have different FFT modes, efficient memory use may beachieved.

When the FFT mode of the preamble symbols is the same as the FFT mode ofthe data symbols of the first partition, if the number of preamblesymbols is an odd number and the number of data symbols of eachpartition is an even number or an odd number, deinterleaving may beperformed as described below.

In this case, the broadcast signal reception apparatus may notconsecutively deinterleave the partitions corresponding to the differentFFT modes, using a single memory. Accordingly, since the broadcastsignal reception apparatus deinterleaves the preamble symbols and thedata symbols using double memories, memory efficiency may be reduced.

When the FFT mode of the preamble symbols is different from the FFT modeof the data symbols of the first partition, if the number of preamblesymbols and the number of data symbols of each partition are evennumbers, deinterleaving may be performed as described below.

The broadcast signal reception apparatus may consecutively deinterleavethe preamble symbols and the data symbols using a single memory (maximumvalue: 32K). Particularly, since the broadcast signal receptionapparatus may perform deinterleaving using a single memory even whenpartitions have different FFT modes, efficient memory use may beachieved.

When the FFT mode of the preamble symbols is different from the FFT modeof the data symbols of the first partition, if the number of preamblesymbols is an odd number and the number of data symbols of eachpartition is an even number or an odd number, deinterleaving may beperformed as described below.

In this case, the broadcast signal reception apparatus may notconsecutively deinterleave the partitions corresponding to the differentFFT modes, using a single memory. Accordingly, since the broadcastsignal reception apparatus deinterleaves the preamble symbols and thedata symbols using double memories, memory efficiency may be reduced.

Accordingly, to allow the broadcast signal reception apparatus toefficiently perform frequency deinterleaving using a single memory, theFFT mode of the preamble symbols should be the same as the FFT mode ofthe first partition. In addition, to allow the broadcast signalreception apparatus to consecutively perform frequency deinterleavingeven when partitions have different FFT modes, the number of datasymbols in each partition may satisfy the following condition.

A sum of the number of preamble symbols and the number of data symbolsin the first partition should be an even number. In addition, the numberof data symbols included in the other partitions is an even number.

FIG. 78 illustrates a procedure for processing single-FFT-mode signalframes by the broadcast signal reception apparatus, according to anembodiment of the present invention.

In this figure, (a) illustrates a procedure for processing consecutivelyinput single-FFT-mode signal frames of different FFT modes by thebroadcast signal reception apparatus, and (b) illustrates a procedurefor processing consecutively input single-FFT-mode signal frames beforefrequency deinterleaving by the broadcast signal reception apparatus.

Specifically, as illustrated in (a), in the single-FFT-mode signalframes, an FFT mode of preamble symbols may be the same as the FFT modeof data symbols in one signal frame, and different signal frames mayhave different FFT modes. This figure shows an embodiment in which thefirst signal frame has a 16K FFT mode, the second signal frame has a 8KFFT mode, the third signal frame has a 16K FFT mode, and the fourth andfifth signal frames have a 32K FFT mode. In addition, a sum of thenumber of preamble symbols and the number of data symbols next to thepreamble symbols in each signal frame is an even number, and each signalframe may include one partition.

Each signal frame may include a bootstrap, one or more preamble symbols,and one or more data symbols. Information carried by the bootstrap andthe preamble symbols is as described above.

Therefore, the broadcast signal reception apparatus according to anembodiment of the present invention may decode the preamble symbolsusing bootstrap information, and decode the data symbols usinginformation carried by the preamble symbols.

As illustrated in (b), the broadcast signal reception apparatusaccording to an embodiment of the present invention may performfrequency deinterleaving on the signal frames received as illustrated in(a). The broadcast signal reception apparatus according to an embodimentof the present invention may perform frequency deinterleaving using theinformation included in the bootstrap and the preamble symbols, and themaximum reception memory size used in this case may be 32K. In addition,the broadcast signal reception apparatus according to an embodiment ofthe present invention may simultaneously perform read operation andwrite operation on input data corresponding to each OFDM symbol, and mayconsecutively perform frequency deinterleaving on the signal frames ofthe different FFT modes using a single memory.

Therefore, as illustrated in (b), if signal frame 0 of 32K FFT mode,signal frame 1 of 16K FFT mode, and signal frame 2 of 8K FFT mode areconsecutively received, the broadcast signal reception apparatusaccording to an embodiment of the present invention may virtually changean input format of the frequency deinterleaver to efficiently performingfrequency deinterleaving using a single 32K memory. In this figure, (b)illustrates a procedure for changing the input format by relocating thedata symbols in each signal frame based on NoA of 32K FFT mode. In thiscase, the input format may vary depending on the intention of a designeror a reception apparatus implementation method.

Accordingly, if the input format of the frequency deinterleaver ischanged as illustrated in a right block of (b), the frequencydeinterleaver may perform frequency deinterleaving using a single memoryirrespective of NoA of the signal frames of the different FFT modes.

FIG. 79 illustrates a procedure for processing single-FFT-mode signalframes by the broadcast signal reception apparatus, according to anotherembodiment of the present invention.

FIG. 79 corresponds to another embodiment of FIG. 78, and shows a casein which the broadcast signal reception apparatusfrequency-deinterleaves only signal frames of one FFT mode using asingle memory.

In this figure, (a) illustrates a procedure for detecting and processingonly signal frames of 16K FFT mode among consecutively inputsingle-FFT-mode signal frames by the broadcast signal receptionapparatus, and (b) illustrates a procedure for selectively performingfrequency deinterleaving on only signal frames of 32K FFT mode amongconsecutively input single-FFT-mode signal frames by the broadcastsignal reception apparatus.

As illustrated in (a), the broadcast signal reception apparatusaccording to an embodiment of the present invention may selectivelydecode only the signal frames of 16K FFT mode. In the case of (a), a sumof the number of preamble symbols and the number of data symbols next tothe preamble symbols in each signal frame is an even number, and eachsignal frame may include one partition. In addition, the broadcastsignal reception apparatus according to an embodiment of the presentinvention may detect signal frames of the same FFT mode using a same FFTindicator carried by the preamble symbols.

In addition, as illustrated in (b), the broadcast signal receptionapparatus according to an embodiment of the present invention mayfrequency-deinterleave only the signal frames of 32K FFT mode using asingle memory having the maximum size of 32K.

Specifically, as illustrated in (b), if signal frame 0 of 32K FFT mode,signal frame 1 of 16K FFT mode, signal frame 2 of 8K FFT mode, andsignal frame 3 of 32K FFT mode are consecutively received, the broadcastsignal reception apparatus according to an embodiment of the presentinvention may detect and frequency-deinterleave only signal frames 0 and4 of 32K FFT mode.

In this figure, (b) illustrates a procedure for changing an input formatof the frequency deinterleaver by detecting only the signal frames of32K FFT mode. Accordingly, if the input format of the frequencydeinterleaver is changed as illustrated in a right block of (b), thefrequency deinterleaver may frequency-deinterleave only the signalframes of 32K FFT mode using a single memory.

FIG. 80 illustrates a procedure for processing mixed-FFT-mode signalframes by the broadcast signal reception apparatus, according to anembodiment of the present invention.

In this figure, (a) illustrates a procedure for processing consecutivelyinput mixed-FFT-mode signal frames of different FFT modes by thebroadcast signal reception apparatus, and (b) illustrates a procedurefor processing consecutively input mixed-FFT-mode signal frames beforefrequency deinterleaving by the broadcast signal reception apparatus.

Specifically, as illustrated in (a), in the mixed-FFT-mode signalframes, an FFT mode of preamble symbols may be the same as the FFT modeof the first partition in one signal frame, and a sum of the number ofpreamble symbols and the number of data symbols in a partition next tothe preamble symbols may be an even number. In addition, the number ofdata symbols included in the other partitions may be an even number, andone mixed-FFT-mode signal frame may include partitions having two ormore different FFT modes.

The figure shows an embodiment in which the first signal frame includespartitions of 8K and 16K FFT modes, the second signal frame includespartitions of 8K and 32K FFT modes, the third signal frame includespartitions of 8K, 16K, and 32K FFT modes, the fourth signal frameincludes partitions of 8K and 16K FFT modes, and the fifth signal frameincludes partitions of 8K and 32K FFT modes.

In addition, each signal frame may include a bootstrap, one or morepreamble symbols, and one or more data symbols. Information carried bythe bootstrap and the preamble symbols is as described above.

Therefore, the broadcast signal reception apparatus according to anembodiment of the present invention may decode the preamble symbolsusing bootstrap information, and decode the data symbols usinginformation carried by the preamble symbols. Particularly, the broadcastsignal reception apparatus according to an embodiment of the presentinvention may check the location and FFT mode of each partition in onesignal frame using start symbol (or cell) information of each partitionand FFT mode information per partition, which are carried by thepreamble symbols.

As illustrated in (b), the broadcast signal reception apparatusaccording to an embodiment of the present invention may performfrequency deinterleaving on the signal frames received as illustrated in(a). The broadcast signal reception apparatus according to an embodimentof the present invention may perform frequency deinterleaving using theinformation included in the bootstrap and the preamble symbols, and themaximum reception memory size used in this case may be 32K. In addition,the broadcast signal reception apparatus according to an embodiment ofthe present invention may simultaneously perform read operation andwrite operation on input data corresponding to each OFDM symbol, and mayconsecutively perform frequency deinterleaving on data corresponding totwo or more FFT modes, which is included in one signal frame, using asingle memory.

Therefore, as illustrated in (b), if a mixed-FFT-mode signal frameincluding a partition of 32K FFT mode, a partition of 16K FFT mode, anda partition of 8K FFT mode is received, the broadcast signal receptionapparatus according to an embodiment of the present invention mayvirtually change an input format of the frequency deinterleaver toefficiently performing frequency deinterleaving using a single 32Kmemory. In this figure, (b) illustrates a procedure for changing theinput format by relocating the data symbols included in the partitionsof the mixed-FFT-mode signal frame based on NoA of 32K FFT mode. In thiscase, the input format may vary depending on the intention of a designeror a reception apparatus implementation method.

Accordingly, if the input format of the frequency deinterleaver ischanged as illustrated in a right block of (b), the frequencydeinterleaver may frequency-deinterleave partitions of different FFTmodes in one mixed-FFT-mode signal frame, using a single memory.

FIG. 81 illustrates a procedure for processing mixed-FFT-mode signalframes by the broadcast signal reception apparatus, according to anotherembodiment of the present invention.

FIG. 81 corresponds to another embodiment of FIG. 80, and shows a casein which the broadcast signal reception apparatusfrequency-deinterleaves only partitions of a specific FFT mode using asingle memory.

In this figure, (a) illustrates a procedure for detecting and processingonly partitions of a specific FFT mode, e.g., 16K FFT mode, which areincluded in consecutively input mixed-FFT-mode signal frames ofdifferent FFT modes, by the broadcast signal reception apparatus, and(b) illustrates a procedure for processing only partitions of 32K FFTmode, which are included in consecutively input mixed-FFT-mode signalframes, before frequency deinterleaving by the broadcast signalreception apparatus.

As illustrated in (a), the broadcast signal reception apparatusaccording to an embodiment of the present invention may selectivelydecode only the partitions of 16K FFT mode. An FFT mode of preamblesymbols may be the same as the FFT mode of the first partition in onesignal frame, and a sum of the number of preamble symbols and the numberof data symbols in a partition next to the preamble symbols may be aneven number. In addition, the number of data symbols included in theother partitions may be an even number, and one mixed-FFT-mode signalframe may include partitions having two or more different FFT modes.

The broadcast signal reception apparatus according to an embodiment ofthe present invention may decode the preamble symbols using bootstrapinformation, and decode the data symbols using information carried bythe preamble symbols. Particularly, the broadcast signal receptionapparatus according to an embodiment of the present invention may checkthe location and FFT mode of each partition in a current signal frameusing start symbol (or cell) information of each partition and FFT modeinformation per partition, which are carried by the preamble symbols,may process partitions of a desired FFT mode, and detect partitions ofthe same FFT mode, which are transmitted in different signal frames,using a same FFT indicator.

As illustrated in (b), the broadcast signal reception apparatusaccording to an embodiment of the present invention mayfrequency-deinterleave only the partitions of 32K FFT mode using asingle memory having the maximum size of 32K.

Specifically, as illustrated in (b), if signal frame 0 includingpartitions of 32K, 16K, and 8K FFT modes, and signal frame 1 includingpartitions of 32K FFT mode and other FFT modes are consecutivelyreceived, the broadcast signal reception apparatus according to anembodiment of the present invention may detect andfrequency-deinterleave only the partition of 32K FFT mode in each signalframe.

In this figure, (b) illustrates a procedure for changing an input formatof the frequency deinterleaver by detecting only the partitions of 32KFFT mode. Accordingly, if the input format of the frequencydeinterleaver is changed as illustrated in a right block of (b), thefrequency deinterleaver may frequency-deinterleave only the partitionsof 32K FFT mode using a single memory.

FIG. 82 is a flowchart illustrating a method for receiving broadcastsignals according to an embodiment of the present invention.

The apparatus for receiving broadcast signals according to an embodimentof the present invention may perform a reverse process of transmittingbroadcast signals which is described in FIG. 1 to FIG. 8, FIG. 10 toFIG. 80.

The apparatus for receiving broadcast signals according to an embodimentof the present invention or a receiver can receive broadcast signals(S81000).

Then the apparatus for receiving broadcast signals according to anembodiment of the present invention or a synchronization & demodulationmodule in the apparatus for receiving broadcast signals can demodulatethe received broadcast signals by an OFDM (Othogonal Frequency DivisionMultiplexing) scheme (S81100). Details are as described in FIG. 9.

The apparatus for receiving broadcast signals according to an embodimentof the present invention or the frequency deinterelaver can frequencyde-interleave the demodulated broadcast signals by using a differentinterleaving sequence (S81200). The frequency deinterleaving is areverse process described in FIG. 30 to FIG. 81.

Subsequently, the apparatus for receiving broadcast signals according toan embodiment of the present invention or the frame parsing module canparse at least one signal frame from the frequency deinterleavedbroadcast signals (S81300). The detailed process of parsing is asdescribed in FIG. 9.

Then, the apparatus for receiving broadcast signals according to anembodiment of the present invention or the demapping & decoding modulecan decode service data in the parsed at least one signal frame(S81400).

Details are as described in FIG. 9. In this case, the signal frameincludes service data corresponding to each of a plurality of physicalpaths. As described above, a physical path is a logical channel in thephysical layer that carries service data or related metadata, which maycarry one or multiple service(s) or service component(s) and the titlecan be changed according to designer's intention. The physical pathaccording to an embodiment of the present invention is equal to the DPwhich is described above.

It will be appreciated by those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

Both apparatus and method inventions are mentioned in this specificationand descriptions of both of the apparatus and method inventions may becomplementarily applicable to each other.

A module, a unit or a block according to embodiments of the presentinvention is a processor/hardware executing a sequence of instructionsstored in a memory (or storage unit). The steps or the methods in theabove described embodiments can be operated in/by hardwares/processors.In addition, the method of the present invention may be implemented as acode that may be written on a processor readable recording medium andthus, read by the processors provided in the apparatus according toembodiments of the present invention.

What is claimed is:
 1. A method for receiving broadcast signals, themethod comprising: receiving the broadcast signals; demodulating thereceived broadcast signals by an OFDM (Orthogonal Frequency DivisionMultiplex) scheme; frequency de-interleaving the demodulated broadcastsignals by using a different interleaving sequence, wherein thedifferent interleaving sequence is used for data corresponding to anOFDM symbol pair or data corresponding to an OFDM symbol according to anFFT size of the demodulating; parsing at least one signal frame from thefrequency de-interleaved broadcast signals; and decoding service data inthe parsed at least one signal frame.
 2. The method of claim 1, whereinthe FFT size is one of 8K, 16K and 32K.
 3. The method of claim 2,wherein a signal frame include data symbols and data corresponding to atleast one data symbol in the signal frame is demodulated by a differentFFT size.
 4. The method of claim 1, wherein the different interleavingsequence is generated by generating a basic interleaving sequence,generating a symbol offset, wherein the generated symbol offset isconstant for two consecutive OFDM symbols and performing a modulooperation for the generated basic interleaving sequence and thegenerated symbol offset.
 5. The method of claim 3, when the FFT size is32K, a single permutation is applied to the generated basic interleavingsequence and when the FFT size is 8K or 16K, different permutation foreach OFDM symbol is applied to the generated basic interleavingsequence.
 6. An apparatus for receiving broadcast signals, the apparatuscomprising: a receiver to receive the broadcast signals; a demodulatorto perform demodulation on the received broadcast signals by an OFDM(Orthogonal Frequency Division Multiplex) scheme; a frequencyde-interleaver to frequency de-interleave the demodulated broadcastsignals by using a different interleaving sequence, wherein thedifferent interleaving sequence is used for data corresponding to anOFDM symbol pair or data corresponding to an OFDM symbol according to anFFT size of the demodulation; a frame parser to parse at least onesignal frame from the frequency de-interleaved broadcast signals; and adecoder to decode service data in the parsed at least one signal frame.7. The apparatus of claim 6, wherein the FFT size is one of 8K, 16K and32K.
 8. The apparatus of claim 7, wherein a signal frame include datasymbols and data corresponding to at least one data symbol in the signalframe is demodulated by a different FFT size.
 9. The apparatus of claim6, wherein the different interleaving sequence is generated bygenerating a basic interleaving sequence, generating a symbol offset,wherein the generated symbol offset is constant for two consecutive OFDMsymbols and performing a modulo operation for the generated basicinterleaving sequence and the generated symbol offset.
 10. The apparatusof claim 9, when the FFT size is 32K, a single permutation is applied tothe generated basic interleaving sequence and when the FFT size is 8K or16K, different permutation for each OFDM symbol is applied to thegenerated basic interleaving sequence.